You may start your tomato plant from seeds or purchase them at a garden center ready for planting. There are many varieties, I prefer Beef Steak Tomato's and cherry tomato's. Plant them in a raised garden spacing the plants 12 inches apart. When the tomato plant's are about 4 inches high, remove the bottom leaves by cutting them or pinching them off. These leaves tend to be disease prone and attract insects. If your plants are bigger than this, still remove the bottom leaves and any yellow leaves. This is a good time to think about caging or staking your tomato's as they will need support as they grow. I use some cages and some stakes. Cages can be bought at any hardware store and stakes are easily made or just use old mop handles and attach them to the plants with a soft cut up cloth or string. But tie loosely so you plants aren't damaged. The little suckers that grow in the joints or elbows should be pinched off, so they won't steal the nutrition from your tomato's. Water tomato's throughly I water every day a really good soaking unless it rains of course. Tomato's that get too little water tend to crack and be deformed. The little yellow flowers are the tomato's and will soon be a nice green tomato. This is a good time to hoe or weed you garden, remove everything that is not a tomato plant. Weeds and grass and anything growing near the tomato's will steal their nutrition. I use a long hoe.
You can fertilize your tomato's every two weeks with ferlizer from your garden centre or organic material if you used manure you may not need much. If you have an insect problem you can use non chemical insecticide, I use Endall and I plant marigolds in the corners as this discourages some bugs. When the tomato's start to ripen water less often but don't let your leaves droop to much that means they need water. Your tomato's need at least six hours of sun a day. I hope they turn out great, nothing like a fresh homegrown tomato's.
Here is a link to how to make a simple raised tomato bed. http://gomestic.com/gardening/how-to-make-a-simple-raised-tomato-garden/