I have tried a lot of stuff: FB ads, SEO, Google PPC, and more. Some have worked (PPC and SEO) while others have failed (FB ads) However, I feel its time to work on cold sales and build a quality lead list - what is the best, most cost-effective way to do this?
Do pro-bono work with brands and influencers locally.
You have to figure out your angle (and maybe you have)
But I personally would begin to network with small businesses in the area who have worked with influencers. I would go in an say that I want to enhance the work that's being done with influencers to increase their ROI -- in that relationship you now have two people-- the influencer who is going to need ongoing work and the business and brand that could hire you separately depending on your work.
I don't think spending a ton of time on advertising when you are a creative is the best route to go-- you need to be creating and leveraging relationships.
Make no mistake though-- when money starts coming in you better HIRE someone who specializes in advertising ASAP. If you could have figured it out, you would have already-- accept that it's a weakness for you and move on to what you know how to do best.
Hope this helps you with some initial ideas!