Some of my recent projects have run into what I call the “too many cooks” problem. Different parts of the client’s branding or collateral were done by different people at different times. The result is that none of the parts — website, identity items like logo and business cards, marketing emails, brochures — look like they belong together. And the result of that is a disjointed and confusing marketing message that doesn’t sell.

Here’s the thing: when a startup has to put together its visual identity (sometimes loosely called “branding”), its marketing message, its sales team and its product line, all the parts have to speak with one voice or they won’t make sense to the public. If one person or agency creates a logo, another one does the website, somebody else designs product labels and none of them are talking to each other, then even if these things are individually excellent the end result will be fragmented at best, confusing to the customer and unlikely to be highly successful.

All the clever social media strategy, search engine optimization and creative ideas in the world won’t drive sales if the website looks so different from the postcard (or the promotional email) that it looks like it belongs to a different company. You think I’m exaggerating? Not so. It can easily get that bad if no one individual with a clear sense of direction is taking care of the project. Too many cooks, not enough coordination, result in an indigestible mess, every time.

One reason brand managers and creative directors are paid the big bucks is that they know not to do things piecemeal. An advertising campaign will use the same look and the same message in magazines and on TV (or YouTube), on billboards, mall advertisements and the website. Of course, they survey endlessly and they work to make the message and the look as effective as possible, but a consistent campaign that dings in the same message over and over again is essential to create interest and bring in high-volume business.

It’s at least as important that all of your public-facing material sends the same message as it is that you get the marketing buttons right. If your direct mail campaign looks beautifully modern with bright colors and great typography, your website had better use the same colors and that same typography. That fantastic photograph on your online product page had better be the same one that’s in the magazine ad, your Facebook page and your promotional emails. Repetition doesn’t just help to drive home the message, it also subtly but emphatically tells the customer that you know what you’re doing and that you take the time to get the details right.

Imagine if the actors, the special effects crew, the costume designer and the makeup people all worked on a motion picture independently, with no director to oversee the entire project. Each of them may be brilliantly talented, but without one person ensuring that all the parts work together, only a miracle would produce a great movie.

Marketing a new business or a new product? Appoint or bring on board a creative firm that also understands marketing to coordinate the entire campaign: your company brand, marketing collateral, website and online marketing won’t be heard if they don’t speak with one voice. Instead of five cooks, hire a chef.