well, my first wed shoot, i brought over 15 kg of stuff, and uses non of them.
1. preparation, if u are not a full pro wedding shooter, do not offer urself for a full wedding job tasks. look for some light one, for experience gains firsts. this it the real 1st step of preparation. 'grab some light exposure/experience first'
2. if it is ur first time, just bring one lens. the lens u are comfortable with. if its kit lens, 18-55 it is. if u are comfortable with 50mm, then 50 it is! (my first wed was with 50mm) very rare cases i will bring 2 lens. (except for FE, which some couple really fancy the shoots from it)
*preparation, make sure ur battery and fully charged, memory is enough. there is once i forgot my flash battery, lucky the shop in the hotel has it, but it cost twice supermarket price!!!!!!!
3. problem, the biggest problem is 'we dare not open our mouth' nothing else. (seriously, ppl walking into our frame, its not even a small deal) as long as we dare to say it out, call it out, or talk it out... problem = no problem. many times, we do not dare to disturb the busy couple just because we wanted to redo a nice compo shot, so, we have to be brave enough to communicate with the couple.

thanx for the explanation ier...for no 3 Q's,i was thinking of sending my vest for embroidery to put Official Photographer or more kejam F Off! I'm The OP...