My dad taught me to throw a steak on a hot grill, wait for blood to just start coming out, turn it once, using tongs ( a fork will allow the juices to run out), and wait for the blood to start coming out this side. The steak is now perfectly med-rare, which is how I like it. If you like it more well done, just let it cook a little longer, it only takes a few minutes. Excess turning, cooking over too low a heat, and turning with a fork will result in a tough dry piece of meat.
I use meat tenderizer on cheap cuts of meat. It works well, if you follow the directions.