Do you like a sandwich whose tomato peeks out from the edges of the bread? If so, grow the big ones such as Big Beef, Better Boy, Parks Whopper, Brandywine, German Johnson, and Super Fantastic. Plant these deeply so that two-thirds of the plant is underground.
Big tomatoes get heavy as they grow, often weighing a pound or more, so tie up the stems to their supports as they grow–you'd hate to lose your prized tomato in a rainstorm because the stem holding it broke under its own weight. You can even use cheesecloth or a mesh nylon stocking to create a sling for extra-large fruit.
A second way to ensure success is consistent watering. Drip systems or soaker hoses are best for putting water at the root level without waste, evaporation, and wetting the leaves. Mulch the ground around the plants to keep moisture in, too.
In cold mountain regions where summer is short, employ tricks such as black plastic to warm the soil, early planting with protection, and continued use of row covers and items such as Wall o' Water to keep tomatoes warmer on cool nights. The Extension service in mountain states is a good local resource for dealing with the weather.