I think the best approach is to read up on asset allocation (other posters have discussed various books and resources), recognize the amount of risk you're willing to take on depending on your timeline, and make a plan for periodic allocations starting now. If you properly allocate your capital amongst different asset classes like stocks, bonds, real estate, commodities, and cash equivalents, you'll probably find a sweet spot for good returns balanced with reduced risk. The plethora of ETFs and index funds out there these days will definitely help with making this simple.

Another consideration is to become a direct investor in some sound businesses. Start looking through your networks. Being an angel investor may not be your cup of tea, but maybe you have friends or families that are running great small businesses. If you have good confidence in a business, there's no reason not to invest. There's a personal connection there, and you're likely to get the boost of great returns as well.