The best place to advertise any service is where your target customers are located. Where do you think you might find people who need graphic design services?
Whether or not I am successful on social media sites isn’t really going to help you. If you are directly connected to your customers on social media sites, then, yes, that would be a reasonable place to promote your services and gain traffic to your gig. The problem is, though, most Fiverr sellers are only connected to their friends or family members on social media. Friends and family are not your target customers. How many of your friends or family members do you think need graphic design services?
Find the people who NEED your services. Those are your target customers. Those are the people who will hire you for your artistic design skills. Those are the people who will build your business. You are going to need to do you research to discover how you can connect to these people. I can’t do that for you. I have my own customers to connect to.
Absolutely! Market and promote your services wherever your target customers can be found. Online, offline, in person. Use other sites. Take out ads. Post targeted advertisements in your community. Use word of mouth. Go wherever your customers are located.
No need to apologize. You just need to realize that as a freelancer, you’re going to have to work hard to find your customers, and connect to them. Sure, you’ll likely find customers on the freelancing sites, but if you want long-term sales, you’re going to have to find them elsewhere as well. And only you know where the people you want to have hire you are located. Good luck!