Peel if needed, then cut all the vegetables into pieces that are basically the same size so they’ll cook at the same rate. Group the vegetables by texture and/or type, so that shorter cooking veggies are on one sheet pan and longer cooking veggies are on another. (For example, root vegetables, squash and potatoes can be grouped together, and cauliflower, broccoli and Brussels sprouts can be grouped together, and onions, zucchini and bell peppers can be grouped together.)