When oil is hot, add diced onion, bell peppers, celery, carrots, mushrooms, broccoli, peas, and garlic and stir fry for about 2-3 minutes, until just starting to soften.
Shake well and add about 1/2 – 2/3 cup stir fry sauce. Continue to cook, stirring frequently, until stir fry sauce has thickened slightly and vegetables are crisp tender – about 2-3 minutes more.