Here is a great little trick for tying knots in thread - which isn't as easy as it sounds when you can't see what you're doing. Even people with perfect sight will find this a good tip! Thanks to Chelle for this one.
First problem is threading the needle. There are devices that can do this for you, though I admit I haven't mastered mine yet. You can always bribe somenody sighted to help though; chocolate works well.
Once threaded through the eye of the needle, pull the thread so that it is level with the other end. (Conventionally you'd leave the end of the thread dangling a couple of inches through the eye, but by double-threading it, knotting it to the other end of the thread, you avoid the chance of unthreading and possibly losing your needle if you drop it, something that can happen easily when you have to use your fingers to feel where you're sewing as well as where your stitches are, and holding the needle at the same time!)
This tip works even if you're just tying a knot in one end of the thread, but we're going to tie both ends together.
First, with your ends pulled together, wind the thread a couple of times around your index finger (the hand not holding the needle). Here's a photo showing this, the thread is wrapped around the index finger and the thumb is resting just on top of the thread, as if you were pinching it between thumb and the edge of your finger.
Now use your thumb to roll the thread off your finger; a motion somewhere between brushing and flicking something off the tip of your finger works well. The result should be a lose tangle near the end of the thread.
Finally find the end of the thread and pull it, and the tangle will form a knot. Ta-daa!
I sometimes find I unravel the tangle, but most times it goes straight into a knot. If you do untangle just re-lick your finger, wind the thread again, slide it off and pull it into a knot again.
It sounds complicated writing it down, but give it a whirl and you'll find it a quick and helpful little tip!
And here's a classic recording of Tie a Yellow Ribbon Round The Ole Oak Tree for you to sew along too!