There are two types of tomatoes - Determinate and Indeterminate. Determinate tomatoes ripen all at the same time - ideal for canning. Indeterminate tomatoes ripen throughout the season allowing for fresh tomatoes throughout the season. Indeterminate tomatoes also benefit from a bit of pruning. I planted Roma tomatoes - a determinate variety and I have Beefsteak tomatoes an Indeterminate variety.
Plant several seeds in one container as not all will germinate and grow.
When you see your first seedling start to appear, remove the plastic cover and put in a well lit warm area. I put my seedlings in a south facing window.
When the tomatoes start to form their first "true leaves" thin out the plants in each container by cutting down the weakest plants and leaving only the strongest plant. Do not try to pull out the other plants because often their roots are intertwined and it will pull out or damage the strong plant. (I learned that lesson last year)Put a fan on your seedlings for about 5 - 10 min a day twice a day to help them develop stronger stems. I live in a pretty windy area so I definitely need strong stems.
About a week before transplanting, place a black plastic mulch down (there are people who say other colored plastic mulch works better, but black worked fine for me last year). This helps raise the temperature of the ground a few degrees before planting the tomatoes. When you're ready to plant, simply cut an X into the plastic where you want your plant. Leaving the plastic on also helps reflect light and heat back up onto our heat loving tomato plants. I live in a colder climate so anything I can do to help keep my plants warm will help them.
Also about a week before planting outside you want to "harden" your plants. To do this, begin by putting the plants outside for a few hours during the warmer parts of the day. Bring them in at night or cover them. Gradually leave them out for longer periods of the day as you see them start to get stronger.
When you put the plants into the ground, put them all the way up to a few top leaves. Tomatoes can form roots all along the stem. Put some sort of cage or support system around the plant so that as it grows it will keep the tomatoes off the ground. It will also give the plant more support and prevent branches from breaking off from the weight of the tomatoes. Be careful not to pierce the stem of the tomato when you put in your stakes or cages.
When the plant has reached about 3 feet tall, remove the leaves from the bottom 1 foot of the stem. They are usually the first to develop fungus problems because they get the least amount of sun. This is also when you want to begin watching for "suckers" on indeterminate plant varieties. These are the new leaf starts that form in the joint of the stem and existing branch. If you catch it soon enough just pinch it off with your finger. If it gets to the size of a pencil cut it with pruners so you don't damage the rest of the plant.
Watering tomatoes - water deeply and regularly while the plants are forming. ie. once a week with a nice deep watering. Tomatoes have deep roots, sometimes up to 5 feet. Make sure you water on a schedule to prevent flower rot, or the brown spots that form on the bottoms of the tomatoes. Once rotting has begun there's nothing you can do. Remove the tomato to allow the nutrients to go to other tomatoes. When the tomatoes begin to ripen lessening the water amount will help the tomatoes concentrate their sugar content, however you don't want to dehydrate the plants either or it may cause the tomatoes to fall off the plant.
I got most of my information from the following site:
http://gardening.about.com/od/growingtips/tp/Tomato_Tips.htm
If you have had success in growing yummy tomatoes, I would LOVE to hear your tips as well. I will post pictures for each of the steps as I see them happening. Here's to another year of experimenting with tomatoes!
