Most consumers discover products and services on the internet, and this has leveled the playing field for all kinds of vendors. A two-person startup with an eye-grabbing web presence can attract customers just as well as a big corporation.

But there’s a catch: With so many options available, the target audience is going to size up a company in an instant. The first impression a company makes will determine whether a potential customer passes or gives it a closer look. And design is largely responsible for that first impression.

But let’s face it: Design is subjective. As with fashion, people tend to be pretty complimentary of their own design tastes. If they think something looks good to them, it must look good to everybody, right? And bec...