Chimichurri is a fresh herb-and-vinegar mixture used in Argentinean cuisine both for basting grilled meats and as a condiment. It's incredible with steak, as you will see!
I was not sure if you wanted recipes for beef tips, or tips for making steaks...since Marlen gave you a recipe for beef tips, I thought I'd give you a tip for making marinated steaks. Hopefully one of us or both of us have helped.