It just takes time, man.
There are neighborhoods I've been driving through for years, just for that reason.
Tips:
Vary the time and day of the week.
Talk to actual humans.
Read area-specific news.
Look at tax records (usually available online).
Set up alerts on your preferred syndicated real estate site - broad parameters, so you'll see new listings both high and low in the range. Look at all of them, and look at how they sell, relative to list price. You'll start to recognize trends. You'll eventually know, just from list price, if something is a good deal or a ripoff. Put the time in, you'll get there.