It is also a good idea to investigate reputation. There are a few ways to accomplish this. One, is to see if they have testimonials from previous clients. These can give you an idea if their clients have been pleased with the products and designs they have purchased. Reviews from Google and Yelp can also help you to get a better sense of the work they provide along with a measure of their customer service. You can also see if the firm has experience working in your field. The more specific experience they have the more likely they are to already have a deeper understanding of your needs. For example, a graphic design firm that specializes in pharmaceuticals may not be the best fit for a hip new coffee shop design.
In addition to graphic design, it is important to find out what other services a firm offers. This may not seem particularly relevant now. However, imagine that you request a logo design and the designer does not have website experience. What if the product you receive does not scale well to fit on your website? Or, what if it does not look right in print? There could be any of a hundred things that do not work out perfectly. If you are paying for a great design, it needs to look great everywhere. This is why selecting a firm that specializes in multiple fields is important. You will want a design team that has web design experience, graphic design experience, and web development experience to guarantee the best results.
You certainly want to have the best graphics that money can buy for your business. Realistically though, every business may not be able to afford $20,000.00 in graphic design costs. That is why you need to find a firm that will work with you and your budget. Freelance designers probably do not have the skills and broad experience to deliver the best product and service for you. Larger design companies may not be willing to work with a small business. For these reasons, your best option is a small to medium-sized graphic design firm that will cater to you. These sized firms will almost always provide the best customer service as well. Their reputation is their key to success.
Finally, does the firm feel right to you? If it is a local business (which is almost always a much better option) did they offer to come out to meet you and discuss your project? If yes, did it seem as if they really cared about your design and project, or did they just care about your money? If they did not offer to meet you, then perhaps they are not the firm with the best customer service.