supplies you will need:
(these aren't really step-by-step directions, but more like tips and guidelines.)
1. begin wrapping the letter with the yarn. my recommendation is to wrap horizontally at first. (though really you can do it any way you want!) and unless you have to wrap a letter with a hole (Bs, Os, Qs, As, Ps, Ds, Rs, etc) you don't need to cut a particular length of yarn.
2. tackle the more difficult areas first (my ex: the middle part of the K). it doesn't have to look pretty in the beginning.
3. keep wrapping, and make sure the "uglies" (where you have to criss-cross to get to other parts of the letter) are on the back side.
4. make sure you cover every single bit of the letter, even the sides.
5. when you're done wrapping horizontally, start wrapping over that vertically. you don't have to, though, this is just how i do it. i learned that i like to wrap the letters in the direction that i would write them. does that make sense?
6. on the back, tie off your yarn (using some of the already wrapped yarn) and snip off the extra.
now you can decorate with your masterpiece, add embellishments, use them as tools to help your child learn his ABCs, or whatever!
here's what i did with mine:
i found this gaudy frame at hobby lobby for half off, and had to get it.
great thing about it is i can use it for decorating AND as a photography prop!