I remember I used to use Seven Seas Italian dressing as a marinade for both steak and chicken fajitas.
For brisket rub with your favor spices, wrap it in foil and smoke it at a low heat for at least 8 hours or when the pile of empty beer cans is up to your knees. If you start it out too hot it will get tough in a hurry, found that out through a lot of trial and error.