Pruning is the main regular job, and the tress should be sprayed as a matter of course against pests and diseases. Check stakes and ties when you prune and at intervals in between. The golden rule is never prune more than is necessary to form a well-shaped tree and encourage the production of fruiting spurs. Under-pruning is better than over pruning.
Young trees require a lot of water in the early stages and moisture can be conserved by giving a mulch of grass clippings in the summer.
Try not to let the trees carry any fruit the first year after planting. It seems hard, but it is kinder to the plants and beneficial in the long run.
Do not grow grass right up to the trunk for the first few years after planting.