My friend, crown molding is the most difficult thing that I have ever tried to do. I bought a compound mitre box electric saw and read every thing I could to learn this task. No luck. I cannot even find a person willing to assist me with this. So many say that you have to cope the joints, I know that that is not correct and why cope when you have the right saw.
You need to take your saw and find a master carpenter that is not busy and see if he/she will assist you.
Once you master it, you can really have fun.
Good luck and if you find some good information, please email me with the site or material.