im kind of new to the whole research thing myself. but i would suggest just start with one thing at first, it can be overwhelming. sometimes things pan out and sometimes they dont. sometimes things that youre zeroing in on can be totally undetectable, and sometimes they are wide open. just start out with one single thing, check it out, and then move on to something else.
for example, just by looking through maps, i have found a section of road which was rerouted sometime long ago. it was rerouted due to a railroad that was to be built, but never was. this original section of road that was abandoned had a church on it. i drove by the other day and could see it was all overgrown, and some huge pine trees were still in the area! and also a lot of woods are in the area. the original road is all overgrown and scrubby, from what i could tell in my drive-by.
i have not detected it yet, as soon as the weather warms up im gonna check it out. im might be good, and it might not.
looking through old maps and pictures is just about as much fun as detecting itself!
a few other things didnt pan out. but one thing is for sure. as you look through maps you will see which roads are the old ones. sometimes it is VERY suprising. for example, i found an old road. nowadays, on one end of the road, it dead ends into a park. on the other end of the road, it is all a newer subdivision. i would never have guessed that at one time this was a "major" road. nowadays it isnt even connected!!
stuff like this is so interesting to me let alone being able to find new areas to metal detect. take yourself back in time. put yourself into "time-travel mode".
well this is what i have picked up so far, good luck!