Graph paper will help keep your letters evenly spaced. Start by writing in your 'hidden' words (you can write them forwards, backwards, sideways and diagonally), then fill the empty spaces with random letters.
Free internet programs will make word searches for you. Type in the words you want to hide and it organizes and creates a word search for you. Print it out and see if you can find all the words.
Make this a family activity: Everyone makes a word search, then trades.
This activity promotes literacy, spatial planning skills as well as word identification skills.