Hi Tigra. We have a delicious method of preparing fajita meat. Marinate a few pounds of flank steak (or whatever meat you choose) in a mesquite marinade overnight. Fire it up on the grill until it's barely pink or cooked through, depending on how you like it. Cut into 1" strips.
For tortillas, you can put them on a plate lined with a damp paper towel on bottom and top of tortillas and microwave them for about a minute. Supermarkets sometimes carry tortillas made with sundried tomatoes or chili peppers. They are usually in the deli areas here.
As far as the trimmings, guacamole, shredded cheese or cheese sauce, lettuce, tomatoes, pico de gallo (a tomoto relish type thing that is hot), and sour cream are pretty much the norm. Sometimes it's nice to have lemon wedges handy for an extra kick. You can also add a bit of lemon juice to the marinade. Works well on all meats. Enjoy!