Hey there, congrats on getting this far. That being said, I'll just give a few tips:
1. Pick a major that you like and is marketable. This will allow you to succeed since you enjoy the subject matter and can achieve strong grades (by building a strong foundation in the fundamentals). Also it gives you an alternative path if you so choose not to do medicine. Medicine is not for everyone and it is perfectly ok to do something else.
2. The first two yrs of UG matter more so than the last 2 yrs in terms of how GPAs are calculated. So make a concerted effort to not take on too many courses (especially concurrent pre-reqs) during those first 4 semesters (or 6 quarters) and make sure you develop good studying habits. The goal is to keep that sGPA and cGPA is the 3.7+ range.
3. Read the textbooks, do tons of practice problems, go to review sessions, utilize the tutor center (or whatever your institution calls it), consult YouTube and Dr. Google and don't stress out too much if you don't understand concepts right from the get go - strive to continually improve.
4. Get involved in research and find a topic you're passionate about - sure bench research (typically life sciences) tends to be the go to but you really need to learn how to apply the scientific method and there are quite a few avenues that will suffice (engineering, physical sciences, clinical research, field research, psychology based research, social science, etc.).
5. Don't rush studying for the MCAT - it's better to delay and do well once than multiple attempts due to ill preparation. Of course spread your clinical experiences (volunteering, shadowing, etc.) over your UG yrs.
5. Take a gap year. I'm serious - medicine is a long marathon and having at least a year to be an actual adult, gain some perspective, and grow before going into the meat grinder that is med school + residency, will either strengthen your resolve to continue or point you in another direction.
I may have missed some things, but those are some tips that I feel are quite important for your success in UG and beyond (or at least up to the point in which you're interviewing for med school). Hope this gives you an idea.
