Read your favorite books, magazines, websites and the liner notes of your CDs to find a word that has special meaning to you. You may also wish to look at websites of word tattoos to give you ideas, although ultimately you should make your tattoo unique to you.
Look the word up in a dictionary to make sure you're spelling it properly. A misspelled tattoo will haunt you for years to come. If your tattoo is of a person's name, confirm the correct spelling with them. If you want to use a word in a language or alphabet you don't know, find a native speaker and ask them to write it for you. If possible, confirm with another native speaker that the person who wrote the word is correct.
Write the word on a piece of paper, or use a software program or website with a variety of fonts that allows for easy resizing. Make several samples in different sizes and scripts, print them out and cut around the word with a pair of scissors.
Hold the pieces of paper over different body parts to decide where it looks best. You may wish to have a friend write the word on your skin in a similar font so you can better judge how it will look.
Take the piece of paper with you to a professional tattoo shop with a good reputation. Choose an artist based on his portfolio, then discuss the tattoo with that artist. The artist will tell you what is possible given the size and shape of the tattoo and your skin tone. He will also redraw the tattoo to make sure it looks just right on your skin.