The quickest and easiest way to have a go at spinning your own fibre is to use a drop spindle. In this instructable I'll go through the basic method of creating a 2-ply yarn ready for knitting.
There are lots of ways to purchase fibre, and, for this, I have used Corriedale Roving, commercially prepared and dyed. It's tempting to use lovely smooth fibres, like merino and alpaca, but these are very slippery and tend to split a lot easier when you're learning how to spin, so something a bit coarser, and "stickier" is easier to work with.
I started by pulling my fibre apart slightly, to make it less bulky than the original roving. The more you can seperate the fibres at this point, the finer the yarn will be at the end.
Step 1: Spinning Singles
All spindle spun yarns begin with the spinning of a single ply of yarn. Traditionally, the single plies are created using an "S" twist, where the spindle is spun in a clockwise direction.
To start, gently tease out a thin piece of the roving, to about half a fingers width and around 6 inches long. Fold this piece in half, and slide the hook on the end of the spindle into the fold. (Assuming you're right handed) Hold the fibre in your left hand, with the teased out section appearing between your thumb and forefinger. Hold the shaft of the spindle in your right hand, and spin it fast in a clockwise direction (to the right) - let go of the spindle once it is spinning, and focus on the fibre. To begin with, you're trying to create enough yarn to wrap it onto the shaft securely and create a base for the spinning. Once you've got enough twist into the yarn from spinning, and it starts to look more like string, you can stop the spindle, take the yarn of the hook, and wind it onto the shaft - hold on to it tightly while you're doing this! With the end of your spun yarn that is still attached to the fibre, wrap this around the hook, and start to tease more fibre out of the blob in your left hand. This time, with the fibre you've pulled through, try to fan it slightly in your fingers, to keep some air in the fibre - it'll make it softer and nicer in the end. Once again, spin the spindle clockwise, and let the fibre twist. While the spindle is still spinning, try to pull more fibre through your fingers, keeping it fanned out at it's source. This is a practice makes perfect moment - the more you try, the longer the pieces of yarn you'll be able to create will get, which in turn means that your spinning will speed up, as you'll be stopping and starting less often.
Continue drafting (stretching and pulling the fibre through your fingers) and spinning the spindle until all of your fibre has been used up, and is wound onto the spindles shaft.
Step 2: Plying the Singles
On the shaft of your spindle is now a single ply yarn. These can be used, but are often unstable, and can either fall apart if there isn't enough twist in the yarn, or tangle if there is too much. It is much more stable to produce 2 or 3 ply yarns. The next step will help you to create a 2 ply, using just the fibre you have spun so far.
Taking the end of the yarn on the spindle, trap it between the middle and forefinger on your left hand, with the tail facing towards your palm. The yarn you have created is going to loop around your hand, using your middle finger as a point to turn around. Start from the middle finger, take the yarn around the back of your middle finger, ring finger, and little finger, bring it around the front of your wrist, and behind your thumb and index finger before looping around your middle finger and going back on itself. You need to continue to repeat this looping until the yarn on your spindle is now wound around your hand. Do not wind it tightly, as it will become difficult to complete the next stages.
Wriggle the yarn away from your wrist and onto the palm of your hand. Once you've loosened the yarn loops up enough to do this, you should be able to take the yarn that is currently around your middle finger, and slip it to the back of your hand. It should then be able to all fall down to around your wrist, sitting where a bracelet should.
Find the two ends of the yarn - one should be near the centre, where we started, trapped between your middle finger and forefinger, and the other will be wherever you ran out of yarn. You are going to work with both ends at the same time. Take the two ends, and tie them together. Loop this knot onto the hook on your spindle.
As you spun the single yarn in a clockwise direction, we have to spin the plyed yarns anti-clockwise, creating a "Z" twist. The 2 ends of the yarn should naturally want to twist together in this direction. With the knotted end looped over the hook, spin the spindle in an anti clockwise direction,and start to feed a small amount of yarn towards it. Once the two yarns are tightly twisted together, stop the spindle, take the yarn off the hook, and exactly as before, wind the yarn onto the shaft and "lock" the yarn off on the hook. Repeating the twist and feed process, spin all of your yarn together, spinning the spindle, and winding yarn onto the shaft as necessary.