This instructable will cover the basics of hand sewing - tools needed, threading the needle, knotting the thread, running stitch, basting stitch, backstitch, slipstitch, blanket stitch, whip stitch ...
I'm going to show three ways to knot. The way you knot might depend on what you're sewing, but most of the time it will be whatever is easiest for you.
Lots of pictures, I know, but the knots are color coded. :D
Purple thread - Knot #1 - This is used for doubled thread. Cut the thread right below the eye of the needle. You will now have two tails. Tie these tails in a standard knot. I normally do this a few times!
Pink thread - Knot #2 - This can be used for single or doubled thread. Hold the needle with one hand and the thread in the other. Loop the thread counterclockwise over the needle and pull it through. You'll now have the beginnings of a knot. Guide the loop down to the fabric and tighten - I normally use my finger to keep the knot in place while it tightens. Do this twice!
Green thread - Knot #3 - You'll need to make sure you have a stitch on the back or wrong side of the fabric that's close by. Take your needle and slip it under the stitch to form a loop. Guide your needle through the loop and tighten. I normally do this two or three times.