SAT

First check whether you will be required to provide IELTS or TOEFL scores or not.
About activities, yes they are very important as they reflect on your overall and rounded personal growth rather than focus on only academic achievements. So can start volunteering at an NGO or could get involved in some social activities at school as well. Take time to develop your hobbies and interests, and participate in events and competitions where you have exhibit your talents. You need to have good understanding of your chosen subject, as your expertise in that field will convince the admissions' officer whether you are a good fit for the college or not.

Hi
Analytical reasoning approx. 24 (35 minutes)
1st Logical reasoning approx. 24 (35 minutes)
2nd Logical reasoning approx. 24 (35 minutes)
Reading Comprehension Approx. 24 (35 minutes)
Total: 4 sections92-100 questions
Time : 2 hours and 20 minutes
Details of each section are as here:
Analytical Reasoning Questions These questions measure the ability to understand a structure of relationships and to draw logical conclusions about that structure. The test taker is asked to reason deductively from a set of statements and rules or principles that describe relationships among persons, things, or events. Analytical Reasoning questions reflect the kinds of complex analyses that a law student performs in the course of legal problem solving.
Logical Reasoning Questions These questions assess the ability to analyze, critically evaluate, and complete arguments as they occur in ordinary language. Each Logical Reasoning question requires the test taker to read and comprehend a short passage, then answer a question about it. The questions are designed to assess a wide range of skills involved in thinking critically, with an emphasis on skills that are central to legal reasoning. These skills include drawing well-supported conclusions, reasoning by analogy, determining how additional evidence affects an argument, applying principles or rules, and identifying argument flaws.
Reading Comprehension Questions These questions measure the ability to read, with understanding and insight, examples of lengthy and complex materials similar to those commonly encountered in law school. The Reading Comprehension section contains four sets of reading questions, each consisting of a selection of reading material, followed by four to nine questions that test reading and reasoning abilities.