Be prepared. Believe it or not, some 1L students don't realize that there are reading assignments due at the first class meeting. Few things are more embarrassing than being called on to recite a case in your very first law school class and having to publicly announce that you're unprepared. You should try to have the first several weeks of reading assignments done before the first class meeting. Not only will this help keep you up to speed, but it will also give you more time to outline and study late in the term.
Brief every case your 1L year. Many law school students (especially 2L and 3L students) will tell you that briefing is a waste of time and will advise you to purchase canned briefs. Part of succeeding in law school, though, is developing an analytical model for breaking cases down quickly into their component parts (Facts, Procedure, Law, Reasoning, and Holding). 2L and 3L students have often already done this, so briefing isn't as important for them. But for a 1L student, briefing cases is imperative. You'll be thankful for this advice when you get your 1L course grades.
Make your own outlines. Most law school classes don't come with traditional textbooks, they come with casebooks. Throughout each class, you should be extracting law from the cases you read and integrating that law and your professor's lectures into a comprehensive outline. It is from this outline that you will study for your 1L exams. Don't use outlines produced by others, especially from classes with different professors. Making your own outlines is a great way to study and is the only way to make sure you're studying the right material.
Actively participate in class. Participating in class is a great way to wrestle with the complex ideas that you'll be trying to master in your 1L classes. Participation is also a good strategy for getting to know your professors and other students. In addition, participating by raising your hand to volunteer when you're prepared will often save you from being called on when you're not as prepared.
Study often and early. Students who do well in law school begin their outlines by about the third or fourth class session (at the latest) and study many hours each week for every hour they actually spend in class. A good ballpark figure is that you should spend at least 2 to 3 hours studying each week for every credit you're taking. So, if you're taking 15 credits in your 1L year, you should spend 30-45 hours studying outside of class each week. Although this might seem excessive, it's how book awards (the awards given to the person with the top grade in each class) are won.