Recommendations-
-Use steak cuts for much more tender beef.
-Cut brisket into long 1 inch by 2 inch strips with the grain of the beef. Part freeze these strips so that when you slice across the grain the slices are super thin.
-use baking powder, salt and pepper and a splash of soy sauce to marinade your beef (min 30 minutes). This is called "velveting", it tenderises your meat.