Hi Nicole! Congrats on your engagement and welcome to the forum! I was new to the forum thing, as well, when I found this wonderful site. You're going to LOVE it! As far as venues, that's the hardest part. I'm still trying to decide on mine ha! First thing, choose your location (Cabo, Playa, DR, etc) then check out the thread for that location. Also, check out tripadvisor.com. It helps narrow the resort choices after you choose the location.
Good luck & happy planning!!