I posted a thread exactly like this in the beginning of this year but didn't get a lot of response to it simply because a lot of people on here don't know about stocks or don't invest.
You need to put in a lot of money to get a high return, if the company does well. Google is very expensive. I think they're at $500 a share or something. Good luck with that one.
First thing, you need a broker. Go online. Don't hire an agent. Too expensive. My personal favorite is www.scottstrade.com
Since you're young, here's what I would do. OPen up a Roth IRA through them. Then invest in stocks so the return you get will go directly into the IRA. That way, you won't have to claim anything for capital gain on your tax return. It's deferred so that's the best part. Tax free!!!
Next step, choose what stocks you want to buy. When you buy a stock, you are basically part owner of the company. Yeah, sounds good doesn't it? When you do that, you can tell your friends that you co-own Google or Microsoft, lol. Ok, that's a little too carried away.
I personally know some good stocks, but I hate giving them out. The reason for that is because I'll get blamed if all of a sudden, they drop or in the long run, it may get worse and all the finger comes pointing to me. I just tell people to research it online. Stocks are risky. They make look good now, but a few months or even a year, they may grow sour. It's hard to predict, but projections can be made. Look at the company's income statement for the past 5-10 years, look at their balance sheet, read any news about them, are they bad or good type questions, check for potential growth, how are they doing now, etc, etc. Looking up stock quotes help too. Their PE ratio is important as well as all the numbers they show for each stock.
Final word: financing stocks is an art. There is no fancy math or rules to go by. Use your judgement, get opinions, research the company. That's it. Buy what you can afford to. It's always better to buy low and sell high.
Lenovo for example is a good company to buy earlier in the year. But at that time, who knows what Lenovo is? I didn't know who they are but their stocks jumped a bunch and they were selling for dirt cheap at the beginning of the year. Now it's gone up. Should you have invested in them from the beginning, you would've doubled or tripled your money depending on how many shares you buy from them.