Tamara says...
As a rule of thumb, the crown moulding should be smaller than your baseboards. Assuming you have substantial baseboards (6 ½ inches or larger with an 8-foot ceiling), you can successfully use crown moulding that is 1 to 1 ½ inches smaller. If your baseboards are small or skimpy looking, you should invest that money into new baseboards and do the crown when budget allows.

Tamara Chiarello's interior design company, In Vision, does both residential and commercial work. Send her your decorating questions here.