Most importantly, don't do anything just because you hear it will look good to medical schools. I recently overheard someone saying there were a philosophy/chemistry double minor because med schools liked it. THat's dumb.
Major in what you want, do the ECs you enjoy, and enjoy college. Add in the required medical school stuff on top of it. If you enjoy your undergraduate experience, you should have no problems doing well enough to get into medical school. On the flip side, if you never make it in, then you will already be in the position to get a job you enjoy.
Ignore what others think of you. If you want to be a DO, be one. If you want to go to the caribbean, go there. The redicule others give you only lasts for a few seconds. More than likely, they have already forgotten once you leave. However, you have to live with your choices the rest of your life.
Undergrad overall, regardless of major or whether you're premed or not, isn't that intellectually challenging. The biggest challenge of college is learning all the material in the short amount of time given.
Know how you learn and tailor your study sessions to maximize the efficiency of gaining knowledge. Everyone learns differently; find how you learn and things will be much more productive.
You don't need a 4.0 to get into medical school.
Not everyone gets into medical school. Plan ahead what you will do if you don't get in.
Ultimately, don't be the Biology major who minors in chemistry and volunteers at the hospital. Not only will you absolutely hate your undergraduate experience (unless you truly enjoy those things), you won't have much to talk about with ADCOMS, friends, family, or your future children. Be different. Do what you enjoy, not what is expected of you. Some things you just have to do though, such as clinical experience, but never neglect the things you love for the things that are expected of you.
Most importantly, have fun. You're only an undergrad once.