How to get clients for your new startup?

I have worked as performance marketer for top MNC and now have established single solo company as a start. The problem i am facing is that i am struggling to get clients and leads. I am doing emails to Founder and CEO of startup who might require performance marketing service with every email personally customised to their industry niche and social media links growth but still failing to get any attraction? Can anyone please help me out how to get my first client overboard? I would be highly grateful