Slice chicken, beef, or shrimp into thin strips
Slice bell peppers and onions into thin strips
Heat a skillet or grill pan over medium-high heat
Add oil to the pan
Season the meat with salt, pepper, chili powder, cumin, garlic powder, and paprika
Cook the meat until browned and cooked through
Remove the meat from the pan
Add the peppers and onions to the same pan
Cook until tender-crisp
Return the meat to the pan
Toss everything together with lime juice
Warm tortillas in a separate pan or microwave
Serve the fajita filling with tortillas
Add toppings such as salsa, guacamole, sour cream, and cheese