In a medium skillet over medium-high heat, cook the ground beef until it is cooked through and no longer pink.
Add in the onion and garlic, and cook until the onion is softened and fragrant. Season with chili powder, paprika, cumin, salt, and pepper.
Stir in the vegetable oil to prevent sticking. Cook for 5 minutes until everything is combined.
Heat up your taco shells according to the package directions.
Fill each shell with some of the beef mixture and top with lettuce, tomatoes, cheese, black olives (optional), jalapeños (optional), and sour cream (optional).
Serve warm and enjoy!