In marketing terms, “making an impression” is all about gaining awareness in the minds of your customers.  Every time they see the name of your company, or hear a message repeated, it makes an impression.  The more impressions you make, the more likely it is that they’ll remember you. 

I remember reading a bit of borrowed wisdom very early in my career, and it’s stayed with me, even if the exact wording has faded in my memory:

There’s something wonderful about receiving a really great letter of thanks.  Those words bring back the memory of what originally happened, and allow the reader to re-experience that moment.

For much of our writing, the sentence composition we learned in school will serve us well.  You probably remember the main points:  Write in complete sentences and pay attention to paragraph structure.  Avoid ending a sentence with a preposition.  Never begin a sentence with “and” or “but.”

As they say, you have to know the rules before you can break them.  Why?  Because, particularly when you’re writing a marketing piece, those rules just won’t serve you well.  (That’s a sentence fragment right there, in case you missed it.)