Combine equal amounts of soy sauce and oil in a ziploc plastic bag. Add garlic and mix by shaking bag. Chop basil leaves and add to bag. Remove all stems from the rosemary and discard. Add rosemary leaves. Make sure all the ingredients are evenly distributed, then add the corn starch. This is ONLY used as a thickening agent, so can be left out if you're grilling. Add meat, and refrigerate for an hour. This is a strong marinade and doesn't need any more time than that.
Use this with steak tips for grilling. Cut the tips into 1" cubes, then skewer with cherry tomatos, small Yukon Gold potatos (Already slightly steamed in microwave so they'll cook thru), yellow squash, and red/orange bell peppers. This marinaide is strong enough to really permeate the veggies, and it tastes wonderful.