The command course varies from company to company;
My advise is to have a thorough knowlege of your sops and books, be able to find relevant information quickly etc.
In the simulator use your resourses well, the F/O Cabin crew etc, above all dont rush a decision unless forced to, no matter how stirred up you may feel dont show it! maintain a calm and profesional manner, remember all eyes are on you now!
Good luck.