Do's and Dont's of an MBA program

For the experienced lot here:

1- Any advice for someone starting out on a two year full time MBA program?

2- How necessary / important is it to join and may be lead various business school student clubs? Any tips on how to do this?

3- What courses are an absolute must to be taken regardless of the MBA major?

4- Any advice on securing summer internship and full time jobs later on? How to make yourself standout from the crowd?

5- Any specific study methods?

6- A 20 hour teaching / research assistantship is do-able or not given the rigors of the MBA course work? School in question discourages it strongly.

7- Anything else that you guys think every MBA student should or shouldn’t do?

Thanks.