get a book or 50
the most important one that comes to mind is called "magic and showmanship" by henning nelms, available off of dover publications
its a great book that not only tells you about illusions and the thought process of them, but of the importance of the theater aspect
im extremely active in theater, on both the acting and the tech side (much more on tech but whatever...) and this book really reflects the important stuff in it
also some books that go under the title "illusion systems"
i forgot the author but im sure a google search can help you out
contact me if you need anything else =]