Make the customer area consumer friendly and inviting. It does not have to have an "automotive" feel to it. Although, I have seen many retro auto customer areas that are really nice. I have changed my waiting areas many times throughout my 36 years in business, and the more professional the look, the more people will feel comfortable with your business.
You are judged by how consumers are treated and what the consumer can see. While the entire facility needs to be clean and pro-looking, from the consumer's perspective, it's the customer service area that counts the most.
Make sure the area is clean, organized and equipped with a really nice bathroom. Don't overdue the walls or counter with too much. Sometimes, less is more. With promotions, limit this too. It's better to have the customer focus on one or two promos, then a wall or counter cluttered with promotions.
Lastly, offer treats and beverages. Again, this does not have to been overdone. We offer freshly baked cookies, energy bars, coffee and water. Our cookies have become our signature Customer Area Treat. But believe me, it's not extravagant. But it's consistent. Which is another key point to marketing. And your customer area is you rkey marketing strategy.