For those who aren't good at prec....

[UTComposer]

Another important thing to remember is that percussion REALLY helps segment to a new 'section' of the song. If you have a repeating drum line, and the next part of the song will sound different, or is significantly different enough from the previous section, spend 1-2 measures (depending on your bpm) and change up your kick/snare/cymbal setup. Crash cymbals help, but making your drums a bit quicker for a moment really helps with smoother transitions.