Tomatoes are perhaps one of, if not the most, popular plants to grow. I have compiled a list of tips to try; many I do myself.
Its no more basic than this. Lots and lots of sun makes great tomato plants. They can grow in shady spots but the results will not be satisfactory.
Dark, crumbly, loamy soil is the best. If you have thick clay, work in straw or compost to loosen it (and in time, this will substantially improve all your soil anyway). Adding manure also works.
There's usually two routes: deep or long. By deep, I mean planting so that the more of the plant is actually below soil level. This lets the plant absorb even more moisture deeper from the ground. Plus the plant will develop roots along the stem allowing it to feed better. The other approach is to dig a shallow trench and lay all but the top part of the plant in it covering it with soil. Be sure to remove leaves from the buried portion though. This has the same effect as the deep dig method without the strain of a dig hole.
In good soil, skip conventional fertilizers. Instead try adding a couple tablespoons Epsom salt to the soil before planting. Epsom salt adds magnesium which tomatoes love. Try this for peppers as well. Also try adding crushed egg shells to the soil. The calcium in egg shells helps to prevent disease.
I'm not talking lollipops...I'm talking about the small sprouts that suck nutrients from the fruit. There are two approaches to these. First, you can leave them alone. Other wise, pinch them off. Pinching them off allows the nutrients to go directly to the fruit and leaves. On the other hand, the suckers do shield the fruit somewhat from the sun and helps prevent sun scald. I prefer to leave the suckers alone simply because I have other things to focus my time on.