3 Things to keep in mind when thinking about investing

1. Discipline - When you are going to invest, make a commitment and stick with it. Even if you can only commit to $50/month, DO IT!
Pay yourself first. Always paying yourself helps to ensure your financial future and even if only doing $50 per month it can add up quickly.

2. Diversification - Don't put all your eggs in one basket.
When investing, you don't want to bet your entire retirement on one company. Like you wouldn't want to invest a 1 Million dollar retirement in Google only. Google may do really well in the future, but something could happen and google could crumble.
Mutual funds are a good option because the diversification has been done for you. A good mutual fund spreads your money over 100-300 companies. You could even take it a step further and invest in multiple mutual funds with different purposes/objectives.

3. Dollar Cost Averaging - This goes along with discipline a little bit. If you can invest $50/month, then do it no matter what happens. If the market climbs, then your money is growing, if the market falls, then you are getting more pieces of the pie for less money. If you are investing in a fluctuating market, then you get a lower average cost for your pieces of pie, and usually a higher value.