Of course my first advice is to avoid Ocean drive and Lincoln Road Mall !! (okey okey just 5 mn to have a look...) and just enjoy this city, against all my expectations very pleasant :-) the beauty of Art Deco district in South Beach and it's pastel colors, Wynwood district with this graffitis, bars, cafés, restaurants, all the caribbean influences...
Few addresses in Miami
If you're looking for a quiet place in South Beach, with a reasonable price, in a very cool ambiance, book the accommodation 7th (the on on the left side in the garden) at bars b&b south beach boutique hotel
The must : Sunset cocktails