One of the problems facing a sewing machine technician is the fact that often she/he only services a sewing machine once a year. How do you increase your services?
One way is to diversify. Fancy word for offering something more. Here are some possibilities: offer field services, sewing classes, sewing production services, offer custom services like embroidery or design or alterations, offer selected notions for sale, sell used/refurbished machines, offer scissor sharpening, set up a store to sell related products, open a dealership...
As you consider expansion, remember your overhead costs.
Example, retail sales are fantastic. Commonly, you purchase an item and resell it for 10 to 40% more than your cost. Buy low - sell high. But what about overhead?
My recommendation: Determine your overhead before your expand. Make certain all overhead is covered before investing in retail. The service center may well have enough revenue to cover increased overhead making it possible to expand sales and services.
A strong service center may be able to cover the overhead for a store. If so, then the margins on retail translate to profits. However, retail margins that must cover overhead usually do not. For this reason many stores fail.