It's not necessary to till the ground every time you plant, but it's always best the first time vegetables are added to a site or after several seasons of production. My tiller has been a small electric one for years and it did a good job. But now I have a gas-powered one that can dig better and cover more ground in less time. In new soils, the gas-powered tillers do a better job of turning the ground and go much deeper. Try to till the ground at least 4 to 6 inches deep the first time.
Now it's also the time to test the soil acidity. You can do this with test kits available at garden centers, or you can take a half-pint sample to your local University of Florida Extension office. All you need is a soil acidity or pH test. You are going to be adding the other nutrients, so skip those tests. If you have had a pH test within a year, you can probably skip this part of soil preparation.
Now is the time to mix in with the garden site any lime or sulfur needed as recommended from the soil acidity test. Also, sandy soils can get a lot of benefit from organic matter additions. Some you might consider incorporating into the soil include compost, peat moss and manures. Avoid adding fresh leaves to the garden site unless you can let it sit for several months. Frankly, I don't have this time right now, so the oak, maple and other leaves go on the compost pile. Lastly, scatter a light application of a general garden fertilizer over the soil and till it in an inch or two.