One of the most important things you can do for your business is invest in a good design.
The quality of design of your logo, website, flyers, and everything else promotional directly affects the impression you give your clients.
A poorly designed branding gives the impression that your work or your product also lacks in quality whereas an impressive design could give the illusion that a mediocre product is of superior quality.
Now, if you decide that the best route to take is to hire a professional designer ( which I recommend 100%) there are a few things you should do to ensure you get an amazing branding that truly reflects you and your business.
First thing's first, do your research. Don't just hire the first designer you come across because they're cheap or have a good reputation. Though they might make an excellent job, I would suggest having a look at their portfolio to see if their style is compatible with your taste. You may also want to hire someone whose personality you like. You'll be working with this person often, you don't want to be stuck with someone you despise.
After you've hired the best candidate, please, let them do their job. Obviously you have to give your input. You're paying for it after all. However, remember that you've hired this person because you have faith in their abilities and trust that they know what they are doing.
Negative space is not a negative thing. I've seen this scenario countless times: a designer produces a nice, clean sign or billboard or whatnot. Only to be told that they have to fill in the empty spaces. And I cringe when they ask to enlarge the text, make it bold,italic,underlined, neon green with a drop shadow. Oh, and don't forget embossed. A little tip: less really is more. If you want your message to pop, it's the negative space (if done right) surrounding your message that will do it, not adding 51 effects to it. Which brings me back to my previous point: let your designer do his work. It'll look fabulous, I promise you.