Dense vegetables like artichokes, broccoli, squash and root vegetables can be steamed or blanched until barely tender before grilling. This ensures that the inside is evenly cooked, and helps to reduce the grilling time.
Soft vegetables like mushrooms or eggplant should not be steamed or blanched before grilling. These vegetables absorb moisture like a sponge, which will ruin the texture of them when grilled.
Avoid grilling overripe fruits as they can be too soft to grill properly. Firm, barely ripe fruit holds up much better over the high heat of the grill.
Rotate or flip fresh produce while grilling to ensure even cooking