[Toro]

Since you are new to gardening I would not start your plants from scratch indoors. But instead would buy good healthy plants at a garden center. For tomatoes you're looking for healthy looking compact(not leggy) plants that already have some buds(flowers) on them.

Usual time to plant is Memorial Day when there is little to no chance of frost at night. Tomatoes unlike other plants can be planted deeper than they are when you buy them. I always nip off the bottom set of leaves and plant that portion of the stem underground. This gives the plant a better root system.

Miraclegrow is your friend, especially in pots where the nutrients tend to leach out quicker than a bed. Also in a pot, you will need to water as often as twice a day when it's hot and sunny.