One of your first stops should be LGBT Visitor Center Miami Beach. Here, you'll be able to orient yourself and get some great tips before you start exploring.
You'll soon discover why this South Beach tourist information center is a hit with travelers. If you're looking for other things to keep you busy, Vizcaya Museum and Gardens, Lincoln Road Mall, and Lummus Park Beach are in this area too. They won't take long to get to from LGBT Visitor Center Miami Beach.