Grapes send their roots deep where they can, and they prefer a soil that is rich in organic material. You can encourage growth by adding an organic supplement at planting time and mulching the roots afterward. The site should have good air circulation because grapes are subject to disease in stagnant air.

Grapes fruit on lateral shoots on year-old canes. All grapes require heavy pruning to produce fruit. Leave two whole canes from the previous growing season and two canes cut back to two buds. The short canes will form replacements for the others when they are through fruiting. When fruit forms from side growth along this cane, clip the cane off beyond the next set of leaves. You thereby encourage two new canes that will bear fruit the following year.

More on pruning grapes from The Ohio State University Extension

Grapes need to be fed only nitrogen and may not always need that. If the leaves yellow and there is little growth in the early part of the season, they definitely need feeding. Late feeding during the ripening period can force excessive growth and spoil the fruit. Grapes mildew badly and need good air circulation and often treatment with a fungicide. The classic remedy is copper sulfate.