The front cover is the heart of any brochure. The goal of your front cover should be to grab your audience's attention by creating an emotional connection, a want to read or explore what lies within your brochure.
The best brochures stir up a range of emotions, from curiosity and intrigue, to awe and excitement. If you're designing for an accountant, for example, the trend in that area might be to produce rather stiff, corporate looking designs. Instead, this would be a great opportunity for you to differentiate your client, by opting for a design more in line with the cool, alternative corporate brochure shown above.