A great way to engage readers is to paint vivid mental pictures. Mental imagery has always been a powerful tactic in sales, but it's especially potent in headlines.
When people can picture or better yet feel what a headline says, they will be much more apt to “dive into the copy.” (Ahem, see what I did there?)
Studies show that mental imagery improve credibility, too.
Your thesaurus might be a good tool. But rather than using it right away (as other synonyms might be just as bland and unevocative), think of metaphors, analogies, or alternate words that describe the action or the object, and then look up synonyms.
For example, “How to write profitable copy like a pro” is pretty straightforward. But direct synonyms of “write,” “copy,” or “pro” might not be enough.
A metaphor I've seen is “turn words into wealth.” So by looking up synonyms, you might end up with: “How to mutate messages into money like a master magician!”
(Yes, I know. I love alliteration. They are powerful, but that's for another tip.) 😉