what are some metrics I can gather to see if an area is good to invest in?
See these blog posts:
what do you use to get an idea of whether or not the return on a property will be worth the effort put in?
See this blog post and forum thread:
One thing worth noting... when I've used the delinquent tax list in the past, I've typically sent out neutral letter postcards, asking them to respond. This gives me an opportunity to see the property information, understand it's unique attributes, it's value and see the seller's level of motivation and THEN I'll make the offer with the benefit of all that knowledge.
Based on how you worded your post, it sounds like you may be taking the blind offer approach? This can work too, and it has some advantages over neutral letters (namely, time savings) but if you go this route, you'll have a wider margin of error because you won't be looking very closely at each property before making your offer.