If you really haven't done a lot of investing before, you might want to take a look at mutual funds first. In general, they tend to be a bit easier to research because they focus on a particular area or sector instead of a specific company.
Many financial institutions offer goal-based mutual funds where you set a target when you would use the money. For example, if you plan to retire in thirty years, the early years will have mostly high-risk, high-return stocks but as the years get closer to your cash out, the portfolio will gradually change to low-risk option to minimize loss.