Choosing a creative agency to create advertising for your company can be confusing and difficult. For one, there are a lot of ad agencies out there and they all claim to do different things. The internet is swarmed with everything from one-man production companies to huge corporations seething with employees.
Your best bet is to choose a company that has a few years of experience under its belt with a strong portfolio and isn't too large of a corporation. Don't allow anyone to sell themselves to you or persuade you with false claims of success. Let their portfolio do the talking. The best ad agencies have a strong history and a strong portfolio but haven't grown too big just yet.
If it's commercials you're looking for, you also want to choose a company that has experience with both web and television advertising. When viewing a company's portfolio, ask them how many hits their advertisements have had on YouTube. Ask to see the actual YouTube pages their ads are on and take note of the view count. Make sure they have a few big successes under their belt (videos that have view counts on YouTube over 100,000 views).
Comedy videos tend to be one of the best forms of advertising, so choosing a company that knows how to make a funny ad will increase your chances of having an advertisement made that grabs people's attention and promotes your company.