As I often say, listen to as many sources of information as possible, and learn as much as you can from all of them. Don't be afraid to search for a second or third opinion on how to handle a
I don't agree with every suggestion it makes (many non-spammy senders use open detection that sets off their "web bug" detector, for example), but overall, there's some good info here. Read it, learn from it, and see what easy steps you can take to comply with these guidelines.