You want to prepare your soil for growing, since seeds have all they need to germinate and grow for a while.
What is the pH of the soil? You want between 6.2 and 6.8.
How well does that soil drain? How well does that soil retain mositure?
How much organic matter is in that soil?
What does that soil smell like?
These simple soil test may help answer those quaestions.
1) Structure. From that soil sample put enough of the rest to make a 4 inch level in a clear 1 quart jar, with a tight fitting lid. Fill that jar with water and replace the lid, tightly. Shake the jar vigorously and then let it stand for 24 hours. Your soil will settle out according to soil particle size and weight. A good loam will have about 1-3/4 inch (about 45%) of sand on the bottom. about 1 inch (about 25%) of silt next, about 1 inch (25%) of clay above that, and about 1/4 inch (about 5%) of organic matter on the top.

2) Drainage. Dig a hole 1 foot square and 1 foot deep and fill that with water. After that water drains away refill the hole with more water and time how long it takes that to drain away. Anything less than 2 hours and your soil drains� too quickly and needs more organic matter to slow that drainage down. Anything over 6 hours and the soil drains too slowly and needs lots of organic matter to speed it up.

3) Tilth. Take a handful of your slightly damp soil and squeeze it tightly. When the pressure is released the soil should hold together in that clump, but when poked with a finger that clump should fall apart.

4) Smell. What does your soil smell like? A pleasant, rich earthy odor? Putrid, offensive, repugnant odor? The more organic matter in your soil the more active the soil bacteria will be and the nicer your soil will smell.

5) Life. How many earthworms per shovel full were there? 5 or more indicates a pretty healthy soil. Fewer than 5, according to the Natural Resources Conservation Service, indicates a soil that is not healthy.

Thoroughly composted material - whether it's manure, grass clippings or whatever - does not smell bad. If it smells bad it is not mature and is probably an unbalanced compost pile as well.

It sounds like you made a start with some purchased topsoil last year. Are you adding to the same area then?

The best thing you can do is get some good mature compost. Depending on the size of your garden you can buy it in bags or have a load delivered. You can put up to several inches onto virtually any soil without hurting anything.

You might consider a soil test at your local County Ag Extension Service. Especially if you were very unhappy with the results last year. But it's not essential. kimmsr has some good advice in evaluating your soil

Finally, what went wrong with your earlier compost bin attempt?