Hello Mustapha. You have to find out if your customer base is able to expand or not. Perhaps you are missing certain areas of demand. Or maybe some of your services are not cost-effective any longer. So, verify with a market research what is the current status of those and other aspects, including trends, and offer customized solutions to match actual demand. Do not forget to support your plan with good publicity. Best wishes.
Report Miguel 's answer
I would look at your current brand presence online - this is how customers find you. 1. Make sure you are listed. 2. Make sure that listing is correct 3. Add photos, build personality online. 4. Get your loyal customers to write reviews to build trust with the new base.
From there look at how you can embed yourself into the industry ecosystem. If you are a repair shop (looks like from profile) see if you can build relationships with insurance companies or local tow truck companies. Partner or advertise with used car dealerships etc.
Hope this helps!