Combine lime juice, oil, seasonings and sugar in a large Ziploc baggie. Place your sliced steak in the baggie to marinate while you prepare your other ingredients.
Preheat your oven to 400°F then prepare your sheet pan with cooking spray.
Add sliced vegetables to sheet pan.
Using tongs take steak out of baggie and place on sheet pan.
Drizzle lime juice mixture over all ingredients on sheet pan.
Toss well using tongs, arrange meat and vegetables in a single layer.
Cook at 400°F for about 20 minutes, or until veggies are tender and meat is browned on the outside. Add up to 5 more minutes if needed to finish cooking the meat to your preference.
While the fajita mixture is cooking, prepare additional ingredients like the tortillas, fresh chopped cilantro, shredded cheese, sour cream and sliced avocado.
Serve on sheet pan and build your own fajitas!