If you are a marketeer, you will use the services of an interesting breed : designers. In an agency, chances are that the account manager will handle the relationship with the design team. But you may also may want to work directly with designers. So, what do you need to look for, apart from the obvious technical know-how? Substance.
Before I started Brand Reveal, a good friend of mine with a 40 years experience in design, told me "best design tell stories". That kept me wondering as it seemed obvious. But the way to get there is only via a solid culture, i.e. substance. Today, the briefs on "make it retro" abound and are pointless. For instance, the style of the roaring 20's, Bauhaus and Art Deco, have nothing to do with the 60's psychedelia or Op Art. Yet, they both are "retro". If you do not get these expression subtleties, you will at best achieve a "pastiche", a fake.
If your brand has historical roots, if you want to echo a particular era, your designer must to live and breathe the creative context, so that any translation on your brand brings the correct cues and stories. It takes years of practice and genuine curiosity to get a solid cultural background. This is why I love working with experienced designers: they know, they get down to the point. Is there no space for young designers ? Of course there is, but they need to do their homework and learn about the art, the culture the history that influenced designs. So, forget Illustrator and Photoshop for a while.
If you feel the creative team is somehow alien to the context of your brand, a word of advise: teach them. As a head of the brand, it is your duty to know everything about your brand. Do your wiki search (in several languages), build mood-boards, buy history & design books, raid the archives of the company, be inquisitive, interview retired employees, analyse, build theories. Have fun, because nobody will do it for you.
And finally, give all this knowledge to the creative team. If they have not done this homework already, the research that you will have produced will be of tremendous inspiration. And there is nothing better that designers who are inspired and have a lot of material to refer to. This, is what I call "design with substance". And this is why seasoned designers are worth every penny invested.