Conroe is my home lake, there are hundreds of docks on that lake that will not produce fish, so don't beat yourself up about it, the ones that do get hammered pretty regular. The best advice i can give you is this, learn how to skip (if you don't already know how) and find the docks that are the hardest to get under with deep water close by, or in deep water, skip a shaky head as far back as you can. I seem to catch the most fish on docks that are atleast 6' deep out on the end, i will not fish a dock that is in 4' of water unless it's during the spawn.
One other thing i'll add, you may already know this but, Conroe gets a ton of pressure, and fishes very small!
Good advice, my son proved that yesterday on Conroe. He was skipping way back under a couple of docks, caught some very nice fish. We hadn't had a bite all day then he had 4 all over 4 pounds in a matter of a few minutes. My skipping skills suck, so did my fishing yesterday.