Before you invest a dime, you should create your personal investment policy. This criteria will let you evaluate deals quickly and, more importantly, take action. Without a policy, it’s too easy to do nothing (rather than make the wrong decision.)
Once you craft your policy, when you find a deal that meets your criteria-BUY IT!
Your investment policy should include your big why*, goals, time horizon, risk tolerance, expertise, current cash position, tax consequences and net worth. Check out the sample I've posted or visit Morningstar.com or Investapedia.com.
*This phrase comes from the book the Millionaire Real Estate Investor by Gary Keller & Dave Jenks. Your big why is unique to you but some examples are: early retirement, travel, spending time with family or paying for your children's education.