I practice the same way I used to when I played many years ago. I run the offense only (we used to walk it off) and run the play then go to slow motion and make sure I know what everybody is doing and where everybody is supposed to be. Then I bring in the defense and run several defense options. Again looking at the replays afterward. Then I set the defense to random and run the plays again, this time trying to get a read on what defense is coming. Look for weaknesses, holes, where the coverage is going etc...
Then I flip sides, and run against the offense on the same play.
Also I do not play online cuz I don't have highspeed internet, just so you know where I'm coming from.
Seems like a lot, and maybe I am a nut, but it makes it more real to me.