Cut steak into 1 inch cubes, cut bell pepper into small chunks. Place steak in a gallon-sized ziplock bag or large bowl.
Combine garlic, onion powder, soy sauce, Worcestershire sauce, balsamic vinegar, black pepper, cilantro, and brown sugar. Stir until mixed. Pour over steak and let marinade in the fridge for at least 30 minutes, or up to 8 hours.
Preheat grill to medium-high heat
Build kabobs by alternating steak and peppers on to the wooden skewers. It is helpful to soak skewers in water before use.
Add kabobs to grill and cook until desired degree of doneness.