A summary of what I did, which hopefully helps others prepare;
I read almost every book in the Delta suggested reading list, and took notes. I then studied those notes often, like when commuting to work and back. I signed up for Ready Set Takeoff which was one of the best recommendations I got! Did an Aero Crew face to face prep in ATL which also helped me scope out the Delta HQ and building 1020 where the interview takes place, plus visit the Delta museum. I did an over the phone with Aero Crew to tidy up my app in airlineapps.com, and it was worth it even though I had looked over my app countless times. I did the full Emerald Coast prep package. Really enjoyed that. I took notes from every Sky magazine and paid attention to every preflight safety video. I read the Delta museum website and especially Deltanet like there was no tomorrow. Which by the way, I found a lot of useful information pertinent to being an Endeavor pilot, especially their flight ops safety information. For awhile when I was an FO almost every captain had done the SSP and was willing to give me insight, which again I compiled notes on, and for all the help I am very grateful. The DGI guys right now may not have as much access to first hand accounts, so take advantage when you have the chance to listen. I was more or less a slam clicker during trips for a while, because when I'm home, I'm watching my kid which is extremely time consuming.

If I had it all to do over again I would have used one of those fancy log 10 pro or whatever those programs are that take your flight time electronically and compile it. I think those programs can also print a paper copy of your logbook, too. I gave myself grey hair with my logbooks; making my own electroinc logbook, reviewing my paper logbooks, and adding up time by each individual aircraft by hand to get the airlineapps data right. With a bonafide logbook program I could have spent waaay more time studying instead of crunching numbers and worrying.