Make sure that you select a property in a diverse economic area and it has a growing population.  

While the schools are strong and the summer is great here, the economy is weak, population growth is among the worst in the country, the cost of living is high and property taxes & maintenance costs are very high.  

I am in a large market where about 50% of the population rent.  

You will see that there is correlation of slower appreciation with slower population inflow.

The market has the biggest Baby boomer population.

  (25-40k population).I'm ready to go a little deeper into this, but don't know if I should continue my strategy of finding clean, already rented, newer units OR try my hand at flipping to gain some cash flow. 

Several of the towns you mentioned are shrinking in population.

We didn’t do everything he did but we could see what worked.The last part of your question was about population.  

.- Buy and hold in areas with population and job growth- Currently not looking to buy in CA until prices come down again- Just getting started. 

Having just been on the course, I knew that thorough due diligence was needed so I checked the county populations, local job markets, foreclosures and many other factors, in addition to finding out as much as I could about the properties themselves.