Secondary Reads

Coach:
We are a mulitple, 8-man front (Wide Tackle6). We will run robber, man, and man-free. All DB's use the same technique for run/pass read. We tell our kids to read the UNCOVERED LINEMAN. For the C's this is the OT (he has a LB over him) and for the FS it is the C. We do not have the C's read the TE since many C's have a tough time telling the difference between an inside release and a down block (we see lots of Wing-T).
On the snap, we have all DB's take 3 slow, short steps backwards or 3 shuffles backwards, while looking at their respective key. The DB's can look for one of two things: one is high hat or low hat (I think lots of coaches use this). High hat means pass and low hat means run.
The other read is simply whether or not the lineman that is being read fires across the LOS or not. If the lineman fires out across the LOS, the play is a run. If the lineman DOES ANYTHING ELSE (pull, retreat, fan block, down block, etc.) we tell the DB's to play pass first and then react to run. We got this idea from another H.S. coach and tried it. We had trouble with C's seeing the tackle downblock and guard pull on Wing-T waggle, and the C would fly up while the SE ran by him. This has really helped us, especially young DB's.
We tell all DB's that if they are confused about what's going on, they should simply continue to get depth and then react up to the ball. It doesn't matter if they are late to play the run. We constantly preach that we don't care if the the DB's make a tackle after a long run; we don't want them to make a tackle after a long pass. We tell all DB's that their two best friends on the field are depth and the sideline. We don't want receivers "parachuting" behind them.
Once the DB gets a pass read, he gets his eyes on the reciever and plays the called coverage. There are some coverage reads, based on the called coverage, that the DB's make; but that's another issue.
I hope I've given you some food for thought.