Yep. The class, and a nice selection of reference books for tricky moments:
Strunk & White's
The Elements Of StyleStyle: Towards Clarity & Grace by Joseph M. Williams
These have both been extremely helpful to me.
The main problem with software checkers is the simple fact that they are programmed along business correspondance lines, do not deal well with variables, and are almost useless when presented with fictional devices like colloquial first person, multiple characters with differing regional speech patterns, etc.
It's best to take the class, buy a couple books, and have some dedicated first readers.
Best,
-G.