Unless something goes awry you will pre-clear as all EI flights are now scheduled to pre-clear in Dublin. Your bags will be checked through so you don't need to collect them in DUB but you will be required to identify them with US officials, they will show you an image.
You should follow the signs for transfer in T2, do not go to the exit. Depending on your layover time you might need to go straight to the US pre-clearance, 1h30 before departure would be as late as I'd reccomend. They generally process flights individually so if yours hasn't been called yet don't be concerned. If you want something to eat do that first as there is not much choice at the gates beyond US border and you are not allowed back into the main terminal area.
Apart from that it is just the same as US Customs/Immigration across the pond, they are the same humourless asshats so make sure you follow all the rules to the letter, oh and don't bring fruits, etc to eat on the plane as once past the check you are officially entering US.
It is a bit of a faff but is much better than having to queue up for hours and deal with all that after landing. On pre-cleared flights once you land you should be able to just collect your bags and go, they are treated as domestic arrivals.