After a while say 50 or so you will begin to see patterns in your area.

One of the patterns I have seen when writing Offers on short sales is having the listing agent lower the listing price to your purchase price, most of the time the approved price comes in closer to you Offer. 

Aside from major economical events like the Great Depression, World War II and the Oil Crisis, this is a pattern that has been happening like clockwork for the last 2 centuries.

our plans have been in a constant holding pattern because Snoqualmie has been in such bad shape.  

We also tracked common complaints to see if there is a larger pattern that we can address and learn from.Move-in courtesy calls. 90 days after move in we will call a resident to ask if anything is missing or if there is anything else they need.

If they have a hoodie, baggy pants, their eyes look down when you make contact with a glance, their walking pattern and approach is irregular, etc. these should be red flags to be ready.

Ivan - I'd recommend experimenting with patterns and colors on your envelopes.  

I spent significant time and money trying to find patterns to bank behavior that would allow us to predict the likelihood that a particular property would go to sale for our customers.

I am noticing a pattern here...Nobody is investing in California properties!

I suspect there is a similar pattern in many other cities.