Most of the people who wash out of ground school have one of two problems: either they don't take it seriously, or they fail to ask for help when they need it (as a result of pride, stupidity, or not knowing that they can).
For the average CFI who has had no airline experience or turbine flight time, ground school can be a challenge. But that doesn't mean that somebody that has 100% Cessna 152 time can't make the transition to a CRJ...
Take notes and study with your classmates (a beer after class makes a great opportunity to get to know each other and study as well). If you don't understand something, ask. If there isn't time in class, ask your classmates or instructor during a break. There's no such thing as a stupid question (only stupid people- just kidding!)
If you happen to be one of the lucky people that has upgrading captains, or new hires with experience at another airline in class with you, even better. Lean on them for info! They've played the game and can probably offer you tips.
Here's a link for some great tips on making it through ground school and sim training:
http://aviation.crosswindlanding.com...ingthegame.htm