First, I would say, that if you have someone you know who can show you how to knit, don't be shy; ask them! I am confident they would love to share their hobby (passion... um... obsession...) with you. If you don't have this person handy, there is no reason, especially nowadays with all the internet has to offer, to teach yourself with the help of books and your virtual friends.
So, what yarn, what needles, how to start? Not all yarns and needles are created the same way and I think there are certain choice for beginners that are beneficial.
There are 3 kinds of needles: straight, circular, and double-pointed. All these needles are made from various materials including aluminum, bamboo, plastic, and various woods.
First, let me say, with all knitting materials, including needles, there is a wide range of cost. I did not know this when I went to a local yarn store and bought my first set of double points and paid $23 dollars for them. They are gorgeous and made from rosewood. But guess what? I could also have paid $6.00 for a fine set to get me started. I honestly don't think the yarn store owner was trying to sucker me, though I have often wondered why she carried only those double points exclusively, leaving me to think that that is just what double points must cost. They do not have to cost this much - learn from my mistake!
All needles come in various sizes to correspond with the type of yarn and knitting you want to achieve. Smaller needles are for finer yarns and are good for making socks, things for babies, and lace. Medium needles will help you make hats and sweaters and scarves and blankets. Larger needles will do the same thing with thicker yarns. You can also knit rugs and bags and other things with thicker yarn.
Needle sizes correspond to gauge. Gauge is the measurement of number of stitches per inch and rows per inch in a pattern. Taking your gauge helps you to achieve accurate sizing of particular garments. For beginners, though, you do not need to worry about gauge just yet. I tell you about it just to help you understand why there are differing sizes of needles. If, for example, you have more stitches per inch in your test swatch (which you should always do before you knit a pattern other than something like a scarf or blanket in which size does not always matter), you should go up one needle size. Likewise, if you have too few stitches, you should go down a size in your needles until you achieve the gauge called for in your pattern.
So, what size needle should you choose to begin practicing knitting? I suggest a size 9 or 10 to go with a worsted weight yarn. Worsted weight yarn is the most common size yarn you will find at discount or craft stores such as Michael's, JoAnn's, Wal-Mart, or Hobby Lobby. Its numeric size is "4" which you will often find on the ball band (label).
I would choose a set of straight needles made from bamboo, as they are not as slippery as aluminum. Plastic is somwhere in between aluminum and bamboo. Wood needles are usually specialty needles and will likely cost a bit more. I know that many people will suggest getting the finest yarn or needles you can afford so that you can thoroughly enjoy the whole sensory experience of knitting, but I don't believe in making that kind of investment in any hobby until you are sure it is something you'd like to pursue. You can have plenty of enjoyment while you are learning using inexpensive materials. Just be aware that if you find a cheaper yarn is splitty or doesn't feel as nice or soft as you might like - especially if you are using a cheap, acrylic yarn, such as Red Heart Super Saver - you should know that there are gorgeous, plush, delicious yarns to be had. There are lovely, soft, affordable yarns out there too, but it will take a while for you to establish your own tastes.
Straight needles are used for knitting blankets and scarves and knitting garments in pieces to be sewn together later.
Double-pointed needles are impressive looking! They come in sets of 5 usually and are for knitting things in the round. As their name suggests, they have points on either end. Knitting in the round with these looks impressive, because you are knitting with multiple needles at once, but you actually are still just knitting with two at a time as usual, while the other needles hold your yarn.
Circular needles are used for knitting in the round and knitting flat (as with straight needles). The difference between circular needles and straights is that with circulars you just have the top portion of the needle and the rest is a cable that connects the two. It is nice to work with them for knitting something like a blanket, for instance, as the bulk of the blanket can hang in between the needles on the cable instead of moving from one straight needle to the other. You should note that circulars also come with differing cable lengths - longer cables for bigger projects and shorter for things like hats or for doing arms on a sweater. Pay attention to this when buying your circulars. The length of the cable will be listed on the package along with the needle size. Having too long a cable for a smaller project will make your knitting of that project difficult or impossible.
Again, for beginning purposes, though, you only need a pair of straights, size 9 or 10, bamboo. The size is big enough to feel comfortable to a beginner and the bamboo will keep your yarn from slipping.
Now for the yarn.
Choose a worsted weight or bulky weight (size "5") if you prefer. Choose a fiber and color that feels good to you. I don't recommend wool, simply because it's not vegan and there are animal cruelty issues surrounding it - especially if the yarn comes from a larger company rather than a smaller or local source which you know may treat their animals humanely. There are plenty of plant and man-made fibers out there to satisfy a beginning knitter. Cotton, acrylic, polyester, nylon and even bamboo fibers are widely available. Note that cotton does not have stretch and may feel rougher on your hands than another fiber. Dishcloths are usually made from 100% cotton and are a good beginner project. Just be aware that you may not like the feel of it after a while. It does not bother me, personally, but I know it bothers some and I would not want you feeling badly about knitting in general if you chose a cotton yarn. Also, there are better cotton yarns than others out there too, so shop around. Caron Simply Soft is a very inexpensive, widely available, soft, acrylic yarn that is a nice brand for beginners to try and it comes in a wide choice of colors and prints.
So, now that you have your needles and yarn, how do you start? I started with the children's knitting book by Melanie Falick called Kids Knitting. I found the instructions clear and the pictures in the book are bright and lovely. I figured if children could knit, I certainly had a chance! Kids Knitting is a few years old and can be purchased used for only a few dollars online. You also will likely have good luck at your local library finding it or something similar. But I know that the illustrations in Falick's book were clear to me.
We have the luxury of the internet too, though, and where illustrations fell short, it was a lifesaver! KnittingHelp.com is beautifully put together. She has many, many videos from beginning to advanced stitching and she shows them in the two most popular styles of knitting - English and Continental.
There is no wrong way to knit. I knit English and I hear that it is often easier. I certainly found it easier to hold my knitting English than Continental. Continental is supposedly faster, though I do believe the record-holder in speed knitting (yes, there is such a sport) knits English. Whichever way feels the most comfortable to you to knit, use that and enjoy it!
Other than KnittingHelp.com, Youtube has many, many videos available with different folks giving you instructions in their own way. I have happily used many of these for help with crocheting.
The great thing about the videos, of course, is that you can pause them and replay them as much as you like while learning a new technique.
Next, be happy with making a practice piece rather than thinking you are working on a "project" as you begin. Just knit and knit and knit and be okay with holes and accidental increases and decreases. All knitters make mistakes - even after years of knitting!! I have ripped back the knitting on my current sweater two times in the last three days. That is unusual for me, but it happens. There are plenty of ways of learning how to fix - or live with - your knitting that you will learn over time; you don't always have to rip back. But try to be okay with it; it's a process and it's just part of knitting.
When you are ready to start a project, a scarf is the natural place most folks look. But starting with a dishcloth or hat or headband or something small like that (I did the smaller, children's square hat with pom-poms for my kids as my first project) is quicker and more gratifying. Simply put, scarves just take a long time and you wouldn't want to get discouraged or bored with your first project. You would likely be only doing garter stitch which is knitting back and forth and the length of a scarf can make that tiring after a while. The whole of knitting is made up of two stiches, the knit and the purl stitch, which are simply opposites of each other. They are combined in so many magical ways that make up all the beautiful patterns and textures you can find in knitting. Using these various stitches, scarves can be quite delightful and endlessly creative. But it can get kind of long with just straight knitting. So, do yourself a favor and choose something smaller.
Finally, Ravelry.com is the knitters' and crocheters' community where you will find nearly 250,000 other knitters, crocheters, fiber artists and designers. You will find literally thousands of free, downloadable patterns (including dishcloths!) as well as patterns for sale. You will find groups that chat and become friends on message boards: Do like parrots and knitting? Do you watch NBC's The Office and knit? Do you participate in Civil War reenactments and crochet? Do you homeschool and knit? There is a group for you!!
One of the beautiful things about Ravelry is that not only can you peruse the thousands of patterns, but you can also see how others have done that pattern. So not only do you see the designer's version of the pattern (and perhaps the great photography on the slim and beautiful model), but you can also see all of the myriad of ways the pattern has been interpreted on real people in all colors and fibers. It's a wonderful place that can eat up many hours of your knitting time!! Tread lightly! :) But do sign up. At the time of this writing, I believe there is a 2 to 3 day wait to get invited to join, as it is still in beta status. But it is SO worth the wait; a fantastic resource.
Well, I hoped this has helped someone be brave enough to put their toe into the ocean that is knitting. It's a calming, life-long hobby that provides hours of inexpensive pleasure, as well as always providing something new to learn. I hope you'll give it a try one of these days and be sure to let me know if you do. I'll be happy to cheer you on!