Whatever tortilla you use, lay it on a plate or clean cutting board and arrange the contents on top of it. Warm the tortilla in a pan with a bit of oil, if you want it warm.
Generally, use meats or seafood. Seafood tends to have more of a delicate flavor and texture that can be overwhelmed by heavier meats.
Try lettuce of all kinds, spinach, sprouts, chopped bell pepper (cooked or raw), broccoli (steam it lightly if you prefer), tomatoes, olives, mushrooms, and anything else you like.
