I was perusing the bookshelves here at my brother-in-law's place and came across a book called The Writer's Art by James J Kilpatrick. It's a 1984 book of advice to writers. There weren't lots of ideas I hadn't come across before but he has a marvelous section on words that are often confused and good explanations for the difference so I thought I'd share some with you.
Alternately/alternatively: Alternately means one after the other (the squares on a chessboard are alternately black and white). Alternatively means one or the other: We could go to the movies or, alternatively, we could go out to eat.
Apparently/evidently: Use apparently when the matter is in doubt (he apparently had a heart attack but we're not sure) and use evidently when we are pretty sure that it's true (He was short of breath, sweating, and complained of chest pain; evidently he was having a heart attack).
Bad/badly: I feel badly means there's something wrong with your fingers. If you feel bad, you're sick, depressed, worried, etc.
Compose/comprise: The whole comprises the parts, the parts compose the whole. Only composed works in the passive. The whole is composed of the parts.
Infer/imply: To infer is to deduce (he inferred that I didn't know what I was talking about when I made four basic errors); he implied that I was an idiot.
Nauseous/nauseated. Nauseous makes people sick; nauseated is what we become.
A pair of twins is four people. He was one of twins.
Prone/supine: If you're lying on your back, you're supine. If you're lying on your belly, you're prone.
Sensuous/sensual: Sensuous pleasures are pleasures of the senses (smell, sight, taste, touch, hearing); sensual pleasures are pleasures of the body.
Try and/try to: He will try to arrive on time (correct); he will try and arrive on time (common but incorrect).