Tell me how to NOT get screwed in a bad economy ?

[Par Attaran]

Experienced investors (10 + years) tell me how to NOT get screwed in a bad economy ? I ask this because, nearly every REI meeting or person I've talked to recently has said "The correction and or down turn is coming soon!"

As a 6 month noob, and someone who is in the processes of acquiring a 3rd property tell me what lessons you learned in 2006-2010?  What ends up screwing you over: too much leverage? vacancies? lower rents? too many mortgages? over paying? etc...