If you're composing music for more than one instrument, you know that writing for transposing instruments can get confusing. The following list offers some easy ways to approach each kind:
E flat instruments: Find the relative minor, make it major, and then write in that key. Notes are therefore moved up a sixth, or down a minor third.
F instruments: Just add one sharp or subtract a flat from the key signature and write the music in the resulting key. Therefore, notation is moved up one perfect fifth from where originally written.
B flat instruments: Move everything up one whole tone. E flat becomes F, F becomes G, and so on.