you have to graduate from the highest possible school that you can (The higher end of of the T-14 helps), Judicial Clerkship (Federal appellate level or higher helps a lot), law review, and being the top of your class. This is the criteria for teaching at the top schools. Most schools throughout the tier system have equally high criteria. Although, if you do well at the school you go to, you have a good chance of becoming a teacher at the school. How would it look if some tier 3 school didn't hire any of its grads? I am sure the people from more elite school will have a competitive edge over everyone else, but people from all schools have some fraction of the class that ends up in academia. Some schools just have higher percentages.