What are some signs or tricks to look at when looking for a rental property?
This is pretty much covered here on the BiggerPockets site... but here are my top 5:
1) Deals should be cash flow positive, unless there is a SOLID business reason why not.
2) Screen properties using some rule (1%, 50%, APOD, or roll your own).
3) Do your own (thorough) due diligence.
4) Avoid "analysis paralysis"
5) Always be learning (get better at what you do)
Hope that helps. Good luck!