most efficient way to weed out potential flip/rental properties

[Nick S.]

i'm looking for the forum's advice on the most efficient/effective way of weeding out properties. i'll be living in the property for at least a year. while i live there, i'll be living in it (so property can't be a complete rehab), fixing or improving the property, and then either flipping or renting out the property. 

i've looked at about 18 properties the past 3 weekends (i just started 3 weeks ago). the 18 properties were chosen based on 2 broad criteria: 

1) based on pictures, description, and google street view, choose properties close to the metra (in illinois), in a location with a great high school (>=8 score), and in nice(r) neighborhood.

2) look at zillow for an idea on property values in the neighborhood so that i'm not buying one of the most expensive houses in the neighborhood. if i feel the house i'm looking at is somewhat undervalued because it needs work and there's some room for me to flip, then house passes.

this criteria has helped me weed out 100's of properties, but takes me a bit of time.

i'm curious, is this a good start or are there other ways that the full time/professional investors use? i'm new to this and decided it was finally time to get my feet wet. thanks.