Before you dive into investing it's a better idea to build up a strong savings first. Figure out how to live without at least 10-15% of your post tax income, then have that auto-deposited into a savings account or two, one of which you can't access easily and one that you can. The more you can manage, the better. I put 25% of my post tax income into 2 savings accounts. Build it up to a point where you could live on just that account with all of your "needs" covered for at least 6 months.
Once you have done that, then worry about investing, and shift that money from savings to retirement or other such investments.