Taxis in Tampa need to be called when you are ready for a pickup, unless you are at the airport (go to the baggage claim area) or a special event (Raymond James Stadium and St. Pete Times Forum, Tropicana Field, etc. have Taxi drop off-pick up areas, or in Ybor City they are near Centro Ybor, and cruising 8th Avenue.  At Channelside, they wait outside near Hooters and Valet Parking areas.  You can also call them and schedule at pick up at a certain time.