Please tell me , how to promote gig best ways.
The best way to promote any of your gigs is to go wherever your target customers are, and let them know of that you are offering a service that they need. Target your customers, and fill a need that they have. This does not guarantee sales (there is no way to ever guarantee sales), but it does connect your services to the people that need them. THAT is how you promote your gigs.
You can figure out how you went to tell those customers, and in what format you wish to tell them on your own. You decide how you want to tell them (i.e., ads, blog posts, message board conversations, social media posts). We’re not going to do the promotional work for you. YOU need to do the hard work if you want to be successful.