Cancun here I come....
Hey there!
Well, I have been there quite a bit and can give you some tips
First, ONLY drink bottled water, even if they tell you the water is OK, I dont trust it and you will get sick most likely.
There are lots of restaurants there and quite a few American chains as well. I like El Shrimp Bucket, the wait staff was hilarious, fun and just really nice (they even threw one of the waiters out the window into the water, lmao!)
What else do you like to do? If you like the ruins, I would recommend Chichen Itza or Tulum (Chichen Itza is the most well known, but Tulum is nice because it's on the beach and you can take a break and swim while visiting the ruins). There are also some snorkel parks that are nice but can be pricey, they are Xcaret, Xel-Ha and Garrafon. I have been to Xcaret and it was nice, but crowded. Down south of Can****here are also caves that you can snorkel in. I have been interested in doing that but have never done it, lol!!
There is also Isla Mujeres which is the island off Cancun. It is really fun to go there, and there are places that can set up a day charter to Isla Contoy (an uninhabited bird island). You can fish for your meal, snorkel on the way and it's nice because it's not the typical touristy thing.
Playa Del Carmen is a little south of Cancun and the place where you can take a ferry over to Cozumel. I like Playa Del Carmen because it is what Cancun was about 10 years ago, not so crowded and touristy.
If you are looking just to relax, sit on the beach and sip pina coloda's well, you can do that in Cancun JUST fine and the beaches are wonderful.
For more tips & tricks, go to www.cancun.com but regardless you cant go wrong, it's such a great place!
Have fun!
Judith