Don't let anyone tell you that your copywriting can't be creative. It can take some serious imagination to get the results your client craves. However, that doesn't mean you should start thinking about marketing content like creative writing. When writing the next great novel, it's fantastic for your creative juices to lean towards a certain kind of artistry and beauty. When writing marketing copy, not so much. In fact, if you get bogged down by the art, and forget your goal, you'll likely end up with marketing copy that leaves everyone wanting.
In other words, it's not about you.
If you take a look at these great examples of copy, you'll notice that they all took intense amounts of imagination, but they're still easy to understand and they still get the message home to the consumer. In a novel, it could be great if it takes three or four reads to unpack the authors intent, but when it comes to content marketing, everything needs to be clear and visible from take one.
Your marketing copy defines the brand
So how do you know where to draw the line -- in other words, when does creative copy stop delivering? The easiest way to think about it is to remember that copywriting is one of the biggest parts of branding. Every bit of writing is a chance for the brand to speak to the customer, which means it needs to not be about the writer (like you see in creative writing) but instead needs to be about the brand. And only the brand. Chances are, the person who writes the copy for Jack Daniels is not down home Southern -- but Jack Daniels' brand is, so their copy needs to be.
If you want to be valuable to online marketers, you need to be able to step into another brand's shoes. One of the biggest differences between creative writing and copywriting is that copywriters need to be able to completely remove their personality, and write in the tone, style, or persona desired by the client. It's perfectly fine to inject yourself into your poetry, but your clients probably don't want a piece of you on their website. And that's definitely not what a customer came to find.
...so write for the reader!
Which brings up the final point -- in the end, you're not even writing for your client. The best way to make sure that you avoid writing for yourselves is to remember who you're writing for: the readers. Rather than getting caught up in the craft of your prose as you work, ask yourself if you came to the clients website, and found this, would you be happy? Is it conveying you the right information, or will most readers get frustrated and move on to the next site?
A a copywriter, your readers aren't looking for beauty or art -- they want to find an answer to their problem. They came to your client's website for a reason, and they want to leave with that need fulfilled. If they click away wanting because they found art instead of information, they've clicked away with a negative experience with your client's brand.
So if you're looking for ways to flex your creative muscles (but still create compelling copy) focus instead unique ways to engage the reader -- while still making it painless to get the info they came for. Find solutions where you can do more than inform, without keeping yourself from addressing the needs of the readers. The creativity of copy isn't in the craft of writing itself. It's in how you deliver the message.