The best strawberry sorbet should also be the simplest. There should be berries—small enough to pop several in your mouth, and sweet enough to eat straight with a smile. There should be sugar. There should be some acid if needed, and some salt to make the flavor sing. And that's really it.
Berries like strawberries are rich in natural pectin, so they don't need much to keep their texture smooth when processed into sorbet. The trick, if you could call it that, is to remember an easy ratio. For every cup of berry purée that you're churning, add 1/4 cup of sugar for a velvety sorbet with a creaminess not unlike ice cream. (About 2 cups of halved berries yield 1 cup of purée.)
Lemon and salt can be added to taste, and amounts depend entirely on the sweetness and quality of your fruit. Go with your gut and keep in mind that the base should taste more sweet and sour than you'd want the final product; cold will dull the flavors a bit.
Here's the most important thing: use great berries. Go to the farmers market if you can and buy the sweetest, most aromatic berries you can find. They tend to be much smaller with fewer bland, tart white bits. Junk fruit makes junk sorbet, and the good stuff is really worth it. You'll want to lap this scarlet beauty up for the rest of the season.