Tackle, bait etc depends on where you are going, witch area, witch reef etc. Best would be to ask the skipper before hand what he recommends you take.
Most important thing you guys should know is that the skipper is always RIGHT. Your safety is his responsibility, if something goes wrong he would know best what to do, don't argue with the man, listens what he says and do it. On the flip side of the coin, if you guys behave and listens to what he says, less will go wrong.
Be safe, don't joke around with gaffs, knifes or hooks. When you cut bait, make sure you are seated or you have a very good footing, its easy to slip and knifes flying around and end up in one of your friends. Same applies to hooks, be sure you do it safely, don,t rush it when the fish are biting.
As to sea sickness, don't know, i don't have that problem.
Enjoy and come back safely!!