The main advice for law school is to try your best to learn the material. There are a lot of laws and cases you need to study. I feel knowing the defenses is not too difficult as they are very much easy to learn with each of the infractions. In 10th grade you should try to do some extracurricular activities such as volunteering and internships as well as summer jobs, You may land a job in the legal field. You could also try to shadow a police officer or attorney as their input into criminal laws would be helpful.