Another error that isn't caught by spell check is lightning vs lightening.
I think it's mostly because our minds tend to automatically fill in the meaning. Still, it's worth doing a search before you send your manuscript off!
If something is getting brighter whether in color or mood or attitude, it is lightening (to be grammatically specific, it's the present participle of "to lighten"). If there's a flash in the night, a storm, or a strike of brilliance, it's lightning (usually a noun).
Sometimes the distinctions can seem subtle, but the savvy reader will spot the errors!