Picking and Cleaning of Vegetables
You will need to pick vegetables you want to grill first. Chose healthy pieces of your selected vegetable, and also try to pick all the pieces in same size. Also it is better that they are at same level of preparedness. If some pieces are more ready for consumption and others a bit more raw yet, they will take different time for grilling. So pick pieces of all sizes and level of preparedness. Once you have selected vegetable and number of pieces you want to grill, try to clean them with a soft cloth or an unused brush etc. Try not damage their skin by rubbing too harshly or hardly on them. You can also wash them, as it is even better to allow the pieces get some more moisture.
After you have selected the vegetable and number of pieces, you will need to cut them into further pieces. Try to cut all pieces of same size and weight. The level of thickness of all pieces should also be the same, so that consume an equal amount of time in grilling.
Moisturising and Grilling
Just before grilling the vegetables, you soak the cut pieces in water for some time. It can be from 15 minutes to half an hour. This is to help the piece get more moisture, as during cutting process the vegetables are left out open and their level of moisture can come down. Properly moisturised pieces can properly be grilled. You can grill them and be ready to eat. For making sure that all pieces are grilled properly at the same time, you can use a grill basket for the purpose.