I have to agree with insertcoffee... an edit to the subject line will probably yield a few more informative replies. Additionally, I might point out that the margarita is not typically associated with Miami. You might try a mojito or another Cuban inspired beverage. Or, you can click the link below for 9 other options. Have a great trip to Miami!
Even the airport bars have good mojitos in MIA.
Unfortunately, OP, my stays in MIA have been for work or positioning for flights, so I don't have a good recommendation for you.
You might want to add when you are thinking of traveling, as that might affect the responses you get as well, and any other info you could share which will allow others to help you better.