Grilling flank steak is straightforward and can be accomplished in just a few easy steps:

1. Prepare Marinade: In a bowl, whisk together olive oil, soy sauce, red wine vinegar, minced garlic, brown sugar, black pepper, salt, and red pepper flakes.
2. Marinate Steak: Place the flank steak in a resealable plastic bag or shallow dish. Pour the marinade over it and ensure the steak is well-coated. Seal the bag or cover the dish and refrigerate for 1-2 hours.
3. Preheat Grill: Preheat your grill to high heat for about 10-15 minutes.
4. Remove from Marinade: Once marinated, take the flank steak out of the marinade and let any excess drip off.
5. Grill Steak: Place the flank steak on the grill and cook for 5-7 minutes per side for medium-rare, or adjust cooking time to your preference.
6. Check for Doneness: Use a meat thermometer to ensure the internal temperature reaches around 135°F (57°C) for medium-rare.
7. Rest the Steak: Once cooked, remove the steak from the grill and let it rest for 5 minutes. This allows the juices to redistribute for optimal tenderness.
8. Slice the Steak: Cutting against the grain is crucial for flank steak. This ensures each bite is tender.
9. Plate and Serve: Arrange the sliced steak on a serving platter.

These instructions will guide you to grilling the perfect flank steak that is not only delicious but visually appealing.