My strategy around extracurriculars in college focused on finding a balance between both social and professional groups.
Professional groups can be extremely beneficial resume boosters when applying to internships/jobs, while social groups can help you extend your network and broaden your horizons on campus.
I tried to maintain active membership in 1-2 groups both socially and professionally, and take up a leadership position in at least one of those groups
Professional Groups - I would suggest trying to find clubs that align with your potential career or academic interests. For instance I was part of the "Finance, Banking & investment Society", which focused on helping students build interviewing skills.
Great question! I would recommend starting at a clubs/activities fair. Most schools will put one of these on in the fall where clubs can come and talk about what they do and students can ask questions and sign up to join. The best advice I got before entering my freshman year was to sign up for everything that seemed interesting. By signing up you aren't committing but rather just getting more information. Go to the first few meetings of what you sign up for and see if it would be something you are interested. Try it all and narrow it down from there.
However, while I would recommend trying it all, know that you can't do it all. Don't be afraid to back out or take a step back if it becomes too much. Recognize your limits and balance out clubs with school, work and friends and don't try to take on everything.
Hope this helps!