All lawyers need polished oral skills, whether in the courtroom or meeting informally with clients. Classes that will improve your oral skills are public speaking, a communication law and ethics course, debate, and any class that requires standing in front of a group, large or small, to speak or present your findings. Lawyers need to think on their feet, and the more practice you have in undergrad and law school, the easier it will be when you become a lawyer.
Lawyers use research and writing every day. Taking classes that require writing and research will your abilities in these areas. Although science and business courses may have paper requirements, classes that involve extensive writing tend to be in the humanities department of most schools. Such courses include English classes specifically involving nonfiction writing, political science classes that require research and writing, history classes that require a term paper, and communications classes that require writing persuasive papers.
Coming up with a logical conclusion after your research is another skill lawyers need. A course in statistics will enable you to gather information, analyze and interpret--precisely what lawyers do when working on their cases. They gather information and facts on a case, analyze them under legal principles, and interpret the case in light of the law.
Another class where you can apply analysis and logic is a course on the U.S. Constitution. Studying cases that involve constitutional issues will reveal how various justices read the facts of a case and interpreted how the facts measure up to the law.