If you are the type of business that likes to have sales or promotions, then some forward planning on SEO will be beneficial for you. What you will want to do is consider the name of your promotion based on the SEO competition, and spend a few months of work before the sale to get your website to rank for your target phrase.
The first part is the most important piece. You want to make sure that the competition for that phrase isn't going to be too difficult in order to get quick results. Some things to avoid would be promotions with "athon," such as "Toyotathon," at the end of them. Since this is a fake word, but one commonly used in marketing, it will be complicated to rank for the phrase. Instead, consider trying to utilize a location within the promotion, as well as your service, such as "Sheridan Vaccuum Sale." While this will be a boring promotion name, it will be easier to rank for. You could also make up something completely new, leaving yourself with no competition.