Deciding where to invest depends on what kind of business you are in and the areas where you are having success. Careful forecasting is key to figure out which investments will have the biggest payoffs. It might be that hiring more staff is a good long-term strategy, or that you can launch a marketing campaign for a low cost and big returns. Be careful of over-investing, you want to make sure that your investments won’t force you to run in the red for too long.