Warren Buffett gave a 1-hour class on how not to lose money investing.

Here is a summary of everything you need to know:

- Rule number 1 is don't lose money, rule number 2 is don't forget rule number 1.

- Never risk what you have and need for what you don't have and don't need.

- You only need to get rich once.

- Never borrow money to invest.

- 16 Wall Street geniuses went bankrupt using leverage: intelligence doesn't prevent stupidity.

- Only invest in businesses you can understand.

- Look for businesses with a "moat" that competitors can't cross.

- You should be able to see where that business will be in 10 years.

- Time is a friend of the wonderful business and an enemy of the mediocre one.

- If you wouldn't be happy holding that stock for 5 years without selling, don't buy it.

- Don't buy stocks by looking at the price the next day; you're buying a business.

- Integrity is more important than intelligence or energy.

- Take jobs you love, not the ones that look good on your resume.