Consider Being Single
It sounds rather extreme, but the truth of the matter is that law school requires your full attention. There is not going to be enough space in your life for the law program and a significant other. The relationships that make it through one partner studying law are very strong, and the partner is typically someone who is very independent. Most people simple decide that being single until they get their juris doctor to to be a good idea.
The texts that you are assigned will not always cover the material that you need to know, and they might not give you the examples that you need to really understand something. Take yourself to the library; you don't need to just use it as a study hall. Look up similar rulings and precedents, as this can help you see why something is in place.
The rule that you learned in grade school, high school and undergrad still mattes; participation counts! Head to class early and get a seat in the front. That way, the law professor knows your name and your face. During class, volunteer answers and ask questions. This is something that can make a huge difference if your grade ever ends up on the fence, and it is up to your professor's discretion.
Be Aware of the Possibility of Failure
The people who go to law school are typically people who have excelled their entire lives. Law school calls for the best and the brightest, but the truth is, the curriculum is very difficult. Most law students fail one class or at least have one or two classes that they need to struggle with. Remember that doing badly in a class is not the end of the world. Simply do what you can to cushion the blow and to make sure that you can stand up afterward.
When you are invested in doing well in law school, be ready to give it your all. Law school is tough, so now show everyone that you are tougher!