The dolphin are out there, just not in the quantity or quality that you will find off the east coast or in the Keys. Our west coast dolpin season is just getting started. June, July and August are the prime months.
They are found where the water is clean -- that may be 15 miles off the Clearwater/Sarasota area, or 80 miles. Some favorite spots to find them are at the western edge of Egmont Channel and "Tuna Alley" (an area coined by the late Capt Larry Hoffman) which is about 40-50 miles out of John's Pass at a headding of 240 degrees.
A lot of guys who find them do it as a "secondary" catch. They're anchored up over hardbottom grouper/snapper fishing and they show. You can "encourage" them to show by chumming with a combination of live bait and chunked dead bait. Don't chumm too much -- that'll just bring sharks. Keep a couple of 15lb or 20lb spinners ready with white bait or jigs and have a ball.
Finally, if you're desparate to catch dolphin, take a long weekend and trailer over to Stuart and put yourself up at the Priates Cove Resort, keeping your boat in the water at their marina.
PB