Going On A Cruise?

i'm cruising for the first time in May and i am confused about alot of things, we are going on the Sensation and i wanted to know how getting on the ship works getting off what to bring what nto to bring how to save money about hwo the dining works, like do you ahev to eat in the dining room at all and how does tipping work and also what about cell phone coverage and things like that. really i need to know everything!!! thansk for you help in advance. also we don't plan on doing any excursions in the bahamas so what else do you recommend, well we might do the gl bottom boat but thats all planned so far.