Here's a quick rule:

Take your age, and subtract it from 120. Thats the amount you should have in stocks. So in your case 99% of your money should be in stocks. The remaining 1% you can put into bonds or a money market stable value fund. Bonds are stable, but have little returns. Stocks are volatile, but can have better rewards. Over a 30 yr period the stock market has averaged an 8% increase in value per year. You can't get that with bonds. Having too much in bonds or stable value funds can cost you hundreds of thousands of dollars by retirement age.

Now as far as what funds, you haven't told us what you even have to select from. It's a good idea to diversify into large, midcap, and small cap stocks. They all have their advantages. I would put a good percent in a international fund if available. Pick up a good finance book. Like Jim Cramers "Stay Mad for Life". Lots of good info in there, that I don't feel like typing 2 pages to repeat.

Main thing is watch the funds fees. There are a lot of funds out there ripping people off in fees, and most people don't even notice.

Also if you can contribute more now, DO IT. There is nothing better than starting early. Contributing 15% for 1 yr now, will pay off more than contributing 10% the next 5 yrs. Trust me.

Here's a little comparison. Just imagine starting at your age. The more you can throw at it now, the easier the rest of your life will be.