Total Return Numbers

[Don Dodge]

Hi.  I am completely new to the forum and can't seem to find where to see if this topic has been extensively covered already.  I am new to investing and in evaluating properties using Brandon's parameters from his webinars I'm finding it difficult to achieve the 12-15% Total Return.  Doing a rental property evaluation I can achieve monthly cash flow numbers but can't seem to make the higher percentage returns.  What do you think I'm missing?  Is it that important as long as all of the other numbers make sense? Thanks!