I describe some marketing methods for new business and my favorite marketing method is SEO
Create a website of your product/ services and promote on social media platforms like Facebook, Instagram, and Twitter Etc...
Do SEO of your website. It helps you to get free organic traffic as well as leads.
Create google my business listing of your business. It helps you to get local clients.
Google Adwords: Do keyword research and set up google ads it helps you to get leads or sales for your business.
Visit forums and share values through your unique content, stay consistent it helps you to build your network and through that, you can get a potentially long time clients.