Soak the bamboo skewers in a baking pan of water for 30 mins. This will help to prevent the ends from burning.
Cut all of the vegetables into 1 inch pieces
Go slow, if you don't go slow your vegetables may split, and won't stay on. Slowly push spear the vegetables onto the stick. One piece at a time add tomatoes, zucchini, peppers, steak, mushroom, then start back at tomatoes and repeat until the skewer is full. You want to pack the everything "tight" so that it stays together and is easy to turn.
turn on the BBQ to high, to warm up.
Add the oil, salt and pepper to a small dish and stir.
Once you have assembled your skewers, brush on the oil/salt/pepper. If you are feeling it, give them a little more, salt and pepper.
Turn down the BBQ to medium heat.
place skewers on the BBQ. I like to pack them close so I can use other skewers to "hold" the skewer in the position I want it in.
Every 2 minutes rotate the skewers a quarter turn until you feel they are done. If you have a hot spot on your grill, don't just rotate the skewers, but "trade" some skewers off the hot spot, with some that need more cooking.