Wow, quite a broad question. The credit card is one aspect that can help build credit but your credit score will depend on other things like length of time the accounts have been open, payment history, other consumer loan information (car, home, personal, etc loans), as well as income and the like.
Not sure if your intent is to finance some/all of your business ventures with a credit card, but if that's part of your question, understand it's very risky. The interest rates you'll get are exorbitant and it will take a hell of a return on investment (ROI) to cover the interest generated if you don't pay the balance off in short order.
How Stuff Works has a good primer on the stock market:
http://money.howstuffworks.com/stock.htm
Investing can be in anything from simple savings accounts and government bonds to stocks, futures, arbitrage, etc.
I don't have too much time right now to go into any more detail but I'll follow this thread and hopefully add some more to it in the future.