We help people with this all the time and have help buyers purchase 6 in the past 2 months - in my experience if you are looking to buy it as an investment then you'll want to look for condos that have a 1-7 day rental first as they have the most rental potential, then 14 days and lastly would be 30 days. In addition if it's been a rental that will usually help you have more income faster since a certain percentage of renters tend to come back year after year.
We know condos from Clearwater Beach to St Pete Beach and the best ones our clients have found have been in Indian Shores and Indian Rocks beach because very vacation rental friendly with lots of 7 day or less options. Also there are some in Madeira Beach, Redington Shores, N Redington Beach etc. that do well - just watch for noise on the road as you get closer to Johns Pass. I have found a handful of proven performers along these beaches that consistently do $30-40K annually and even as high as $50K. Clearwater Beach condos typically command a higher price and lower rental options and in my experience it's not geared to vacation rentals so when I've reviewed actual rental history in units like Cresent Beach Club - the ones I've seen have been 1/2 what other short term rentals have demonstrated and the price is 30%+ more - On Clearwater Beach they are very sensitive to competing with their hotels and a few years back banned 7 day rentals of homes on the North end of the beach - a few were grandfathered in but other than that it's a 30 day minimum.
When our clients find communities / condos they like we recommend searching the community in Google and see what kind of reviews the community / unit has - gotten because most renters like buyers are savvy and will typically search online.
Also we don't do rentals, however we always refer our clients to 3 of the most successful local companies that specialize in vacation rentals so they can give them realistic income expectations based on their experiences.
Hope this is helpful, Good luck in your search.
Charles Rutenberg Realty