To tip or not to tip?

I'm curious who to tip and not to tip. Florists, Photographers, Limo (yes), Djs? Is there an unwritten rules about who to tip and not? If anyone knows please list them for me if you can. Thanks alot.
Andrea

This is who we tipped
Florist Delivery - 25
DJ & assistant 100 & 50
Photo & assistant 100 & 50
Video & assistant 100 & 50
Favor Delivery 25
Makeup 20%
Hair 20%
BM - 150
Bridal Attendant 100
Valets - 25 each
Limo (bus) drivers - 25 each
Waitstaff & Bartenders - 4 per head (which was about 650)
Officiant - 50