This is how I picked my resort:
1. First you have to narrow down where you want to have your wedding (Mexico, Jamaica, etc). If you could narrow it down to a town on the island (like Ocho Rios or Negril) or a location in Mexico (Riviera Maya or Cancun) at this point that would be helpful.
I chose Mexico because the flights would be cheaper for guests, and I chose Cancun because 1) the ride from the airport would be shorter, 2) the beaches are fantastic (thus why the area because famous), and 3) access to night life for the younger guests
2. Based on personal preference and the guests you really want to come, decide if you are looking for family friendly or adults only.
My fiance's brother has 3 kids - so adults only was not an option if we wanted him to be there.
3. Decide what type of wedding package you want. Do you want it to have a private reception (ex: on the beach) or is a reception in a portion of one of the resort restaurants what you want?
I definitely wanted a private reception where we could have a DJ and a dance floor.
4. Look at ceremony and reception locations at the resort. Make sure you are happy with at least one of these locations.
I wanted to have my ceremony at a gazebo and my reception on the beach. BUT I didn't want my gazebo ceremony to be right in the middle of everything (ex: right next to the pool) - so I looked for a gazebo where you can actually get pictures of the wedding without getting an old man in his speedo in the background.
5. Then look at resort reviews to help you narrow down the last few resorts. Look at reviews from brides, but also look on tripadvisor for vacationer reviews. Remember that you and your guests need to have a great vacation expereince as well.
Hope this helps!!! Of course there is no wrong selection so don't stress out too much over it.