Deal Analysis Help Please

[Cori White Eagle]

Webinar tonight said 1 criteria is to yield $100-$200/month positive cash flow. Questions: 15 year mortgage vs 30 year mortgage. Large down payment vs Low down payment.  I can "make" any deal generate positive cash flow by extending term of mortgage and increasing down payment.  What is "rule of thumb" for length of mortgage and % down payment when calculating monthly cash flow for deal analysis?  I'm not trying to leverage these to "make" a deal look good.  I'm trying to ensure I don't artificially make a deal look good when it's not.  thanks