gather all the images you want to have on your shirt

draw the characters on the shirt with the pencil

once you're done with all the lines,its a good idea-although not essential-to go over the pencil lines with a black fabric marker
(just so the pencil doesnt get rubbed out while you're painting)

fill in all the characters with the fabric paint

go over all the lines again with the black fabric marker to neaten everything up...
...and...

...voila :)