I used to work for Vanguard. Maybe it's them brainwashing me, but the one notion that stuck with me is to not overlook the fund's expense ratio. Yes, you need to choose how risky you want to be, the balance of stocks/bonds, whether you want index or actively-managed funds, etc. but after all of that, if you have several candidates, pick the one with the lowest expense ratio. Often times, the benefits of a super-duper awesome fund manager who makes all the right decisions can be erased by higher overhead, and you never know when the fund manager will throw a seven. You at least have some idea going in what the expense ratio is, at least historically.