Beef tri tips can be prepared several ways before smoking. They can be seasoned with just a bit of salt and pepper, which allows the flavor of the beef to shine through. You can also use a dry rub seasoning mix to give the tri tip more flavor. Onion powder, garlic powder, red pepper, black pepper, salt, and other seasonings can be used. Marinating the tri tip is another option for seasoning, and there are lots of recipes you can find that will work.
When it's time to smoke the tri tips, cook them just long enough to bring them up to medium rare or medium done. Let them rest for 10 minutes or so before slicing to serve.