This post is partially reposted from Crochet Camp to help the newbies out. Yarn is the same for crochet and knitting, so skip ahead to needles if you've got the whole yarn thing...
Starting out, it is so very easy to be overwhelmed by the amount of choice when it comes to yarn and needles. There are just so many: acyrlic, wool, silk, alpaca, wood, plastic, metal.
My advice for starting out with any new craft is always the same:
1. Start with a pattern you want to make. Starting from something is so much easier than starting from nothing. Plus, finding a project that you really want to see finished is a great motivation to learn the skills needed to complete it. If a garter stitch scarf is really what you want to make, great. But for many people it will be rather dull.
2. Ask for help. Be it online or in person, a granny, a friend, a blogger or the staff at your local yarn store, people who knit usually want to share the love. When in doubt - Ask!!
Starting out can be slow and frustrating, like any new skill, but in the end you will hold something in your hands that YOU made. Pretty awesome, if you ask me.
No matter which pattern you start with, you will need the 2 basic supplies of yarn and needles to get going.
The pattern you have chosen should tell you the kind of yarn you need. Yarn is graded by its thickness - starting at extremely fine lace and cobweb yarn and moving up to Super Chunky/Bulky.
Yarn is graded on how many "wraps per inch" one can measure. In a nutshell, if you were to wrap your yarn around an object, and line each wrap up as above, how many times around would measure 1 inch? Now, this isn't something you need to know or memorise when you are buying yarn, but it can be a useful tool for thinking about how the thickness of each yarn weigh compares.
Generally speaking, thin yarn makes smaller stitches and a thinner, more drapey fabric. Thick yarn makes bigger stitches with a thicker, often stiffer fabric.
When picking a project as a beginner, it is a good idea to start with a smooth yarn that is a DK, Aran, or Chunky/Bulky in a light colour. This is a nice middle ground, where the yarn isn't too thin that you can't see what you are doing, but not too thick that it is unwieldily. A light colour (and a smooth texture) will enable you to see what you are doing.
With the rise in popularity of knitting and crochet, there has also been an increase in the kinds of yarns available - from fuzzy eyelash yarn to wool in every sheep breed imaginable. Broadly speaking you will find manufactured fibers, natural fibers, and some combination there of in your online or local shop.
Acrylic yarn is a manufactured fiber that is very light, very cheap and readily available. A few dollars or pounds can buy enough for a child's jumper - hard to match in any other material. Acrylic is hypoallergenic, vegan and rarely requires special washing techniques.
There are some drawbacks to working with acrylic. It can sometimes feel a bit strange on your needles often referred to as "squeaking", it has a tendency to pill, and can result in static. Using a yarn that is a blend of acrylic and wool can minimise some of these factors.
From the softest Merino to the naturally tweedy Shetland, the variations available in 100% wool is astounding. Wools is often lovely to work with, with none of the "squeak" of acrylic. The amazing properties of wool has been documented elsewhere, but it is an excellent temperature regulator and can resist and absorb water, without the wearer getting wet. Also, as a beginner, it is very resilient and can be pulled out repeatedly (if you need to).
Wool yarns can be more expensive than acrylic. They also may require special care, so check the ball band for washing requirements. Superwash wools have been specially treated not to felt. Wool is often blended with other fibres to give the yarn the qualities of both, for example nylon is often blended with wool to create harder wearing materials for socks.
Cotton and Bamboo:
Cotton yarn is very smooth, giving great stitch definition. It doesn't have much stretch in it, so if you are a tight knitter, it can be a bit tricky. Quite inexpensive and resilient, cotton makes a great material for homewares. Bamboo has many of the same properties as cotton, but tends to have more sheen and drape.
The list of fibres that can be made into yarn or blended with one of the above, is endless. Silk, alpaca, soy, milk, cashmere, and mohair (even camel!) fiber adds interesting and unique textures to yarns. These types of fibers do tend to be more expensive, but they can be worth it for that special item.
The best yarn for starting out will be smooth, with a good amount of twist in it. Wool, Acrylic, or Cotton blends are good places to start.
Knitting Needles generally come in 3 types: Straight Needles, Double Pointed Needles and Circular Needles.
Straights come in a variety of lengths and materials. The brightly coloured vintage needles that so many people have lying about are made from plastic. Though plastic needles are still available, most knitters use wood or metal. Straight needles have a point at one end and a stopper of some kind on the other. This keeps the stitches from falling off. Straight Needles can only be used for working in rows.
Circular Needles are have pointed metal, plastic or wood tips connected to each other with a cable. Circular needles can either have fixed length cables or interchangeable cables. Circs can be used for working flat or in the round.
If you are struggling with coordinating your straight needles, it is worth considering trying out a circular needle. With just the tips to control, they can be easier. I knit only with circular needles.
Double Pointed Needles
Double Pointed Needles (DPNs) come in sets of 5 or 6. They are used primarily for working in the round in small circumferences - often socks, sleeves, and hats are worked on DPNs.
Knitting needles come in a range of sizes. The diameter of the needle determines the amount of yarn taken into the stitch. Usually one uses a larger needle for thicker yarn, but this isn't always the case.
When it comes to choosing needles, its a good idea to try out a few and see what you like - straight, plastic, circular or wood - a single pair of needles isn't usually expensive and can often be found at charity shops or on eBay.
This post is part of Knit Camp.