3 things make a good build thread:
1) Lots of pictures of the build
2) A good statement in the first post of how the build is planned to proceed. Over what time, any planned modifications, etc.
3) Be sure to include a final flight report including photos. Add Video if you have a video camera.
The best build threads occure when several builders join the thread with info from their build of the same kit/plane. Now the story of one build becomes a collection of tips and photos and advice from many builders. This becomes a real resource to future builders. Sometimes the kit manufacturer will post a link to that build thred to supplement their own instructions.
I love build threads, even if I never plan to build that plane.
Stickeys usually occur because numerous people send notes to the forum moderator recommending a thread as very useful/valuable/helpful. Or the moderator spots such a thread and decides it should be a sticky.