Originally Posted by
PossibleDeviation
No. Biggest piece of advice is come in instrument proficient. OO isn't going to teach you that.
This. Study the Instrument Procedures Handbook. Know how SIDs and STARs and "Climb/Descend Via" works. Know the differences between the various flavors of GPS approaches. Get familiar with the stuff pertaining to Part 121 ops. Study Jepp charts so you're not hunting for stuff on them when you start using.them.