Most templates do it by tucking everything away in a folder in the project panel except for the composition you want them to render (which is titled "MAIN RENDER" or "RENDER ME" or something) and a folder containing pre comps that they need to put their text/logo/images in. That way, when they place their images in the respective pre comps, everything you've set up will work!
- The Great Szalam
(The 'Great' stands for 'Not So Great, in fact, Extremely Humble')
No trees were harmed in the creation of this message, but several thousand electrons were mildly inconvenienced.