Here are my pieces of advice:
1) Do not pick your bridal party too early- if you get engaged longer than a year before your wedding wait until at least the year mark or less. I learned this from my friends as they picked their bridal party too early and there was at least one person they wish they would have included and or gotten rid of once the big day got closer.
2) It is your day and it does only matter what you want. When you get those No's back your heart does sink and you get disappointed- but when you are in Mexico or wherever your wedding is- you forgot about those people that didn't come. My motto for my wedding was "It's their loss" they have to hear about how much fun we had in Mexico for the rest of their lives- sucks for them haha. Don't sweat the small stuff- if you do not get in contact with your onsite wedding coordinator a week or a month before you wedding- don't worry- it will all work out- these ladies are AMAZING and this is their job and they will make all your dreams come true!!!
3) I def agree with Allie Pick a good photographer- your pictures are all you have after your wedding is over- I love looking at my 800 plus photos. And keep in mind it might actually be cheaper to fly a photographer from your hometown vs hiring local to your wedding location. I contacted a few local photographers from home and asked if they would be interested if doing a destination wedding! I ended up getting a photographer for 3 days with a TTD session, some rehersal dinner shots and ALL day and night wedding coverage (10 am to 10pm) for the same price as I would have gotten a Cancun photographer for 6 hours on the wedding day. So don't be scared to ask!!! Oh and she did our engagement photos at home so we got to know her a little bit better before our big day and that was also included.
4) I recommend this which is something we were not able to do because we were married in Nov and my husband started a new job in Sept so he did not have much vacation time- but def take a couple days after the wedding and switch resorts or make everyone leave the resort and stay longer. We spent a week in mexico- and about 12 people stayed the full week with us and the rest of the people (we had 39 total) stayed for 5 nights and we did not get any alone time as we didn't stay longer than our guests. I feel like I got cheated out of my honeymoon as we felt obligated to eat and hang out with our guests the entire time. So the hubby better be taking me on a "honeymoon" for our one year anniversary!