Hi Dianne, The basics on pruning can basically be summed up in one word......DON'T. <G> Tomato plants usually need to be supported and contained but pruning is usually undesirable. The fruit is set at the ends of the shoots and more is set as the shoots lengthen. Any pruning stops further fruiting past the point of the cut. Stakes, with each plant restricted to two or three shoots are OK for a few plants but wire cages do immensely better for me. I don't prune at all and just poke the wayward branches back into the cages. Red Robin is a dwarf and requires no support while Mortgage Lifter is a big determinate that needs strong support up to 7-8 feet high when well grown. I usually let the vines trail back toward the ground after 7' so I don't have to use a ladder. The only time I can see pruning is when vines insist on running into undesired areas. Good gardening, Chuck Wyatt