T.M.
My mom was a professional cake baker and decorator when I was a child, (imagine the amount of dishes I had to do!). Anyway, I used to sit in the kitchen and watch everything she did. From time to time she would have a cake that came out close to perfect, but never all the way perfect. She would cool the cake and then flip it upside down using the bottom of her cake as her pallett to decorate. If she felt the dome was too high on the top of the cake she would trim it before she would flip it, otherwise you risk the cake cracking. Also, she would sometimes freeze the cake before trimming because it helps keeps the crumbs to a minimum.
I know techinques and styles have changed in the past 20 years so others may have better techniques to offer but from my experience this way works pretty good as well.