In a large skillet on the stove, heat the olive oil and toss in the steak and cook for about 5 minutes over medium-high heat. Toss in all the vegetables and reduce heat to medium.
Sprinkle some more fajita seasoning if desired. Cook everything an additional 5 minutes.
Remove from heat and serve with flour tortillas, shredded cheese and sour cream, salsa and guacamole.