If you have something that outperforms SEO or PPC for generating sales, then you have something special on your hands.

SEO, Email Marketing, and Paid Search generally dominate online marketing as it relates to driving sales. This is true across most, but not all verticals. It is generally the case for eCommerce although social media can sometimes be more effective in certain categories.

Since this is well-known among eCommerce marketers, the best chance you have to validate your bold claim is to show bold results. Case Studies and testimonials will open the door for you. If ROI is 100% trackable, then this is the metric that you should focus on almost entirely.

From there, I'd suggest that you do two things:
1. Being a direct sales campaign focused on your target audience of ecommerce marketers.
2. Utilize your own platform to generate additional sales.

While you will likely not replace SEO or PPC, you could become a valuable addition to an eCommerce company's marketing mix.

Let me know if you're interested in discussing this further.

I agree with Jeff here. If your ROI really is trackable and if it converts as well as you say, then I'd try to get some excellent testimonials ASAP.

If results are that good, getting some excellent testimonials will help your customers do the selling for you.

Try offering a trial to a few key players - folks who have influence over others in your audience.

Also, look for other partners - Anyone who has influence over your target market because, once you have a few amazing testimonials (and I don't mean lots of superlatives in the headlines here... I mean like:

"How [Big brand name] saw 'x00%' ROI in 'y' Days..."

Then I'd go for some partners and offer them an affiliate/referral deal to get your next few sales.

If Ecom is your target market too, how about running platform-specific offers or deals? E.g. Woocommerce users (ads to them), Shopify users (ads to them)... And/or partner with Woocommerce designers, Shopify designers etc... folks who influence the people you're targeting and are already trusted by them.

Win over 1 or 2 Shopify / Woo designers by showing them great results and offering them a % of sale... you stand a chance to grow faster as they'll likely have the ear of ecom site owners, and be trusted by them.

Sorry if this is a bit of a convoluted suggestion... I have man flu today so am not thinking as clear as normal!

You are trying to get people to switch from a service that is already very effective and proven to one that is risky. You will need proof that it works before anybody will pay you money for it, so start by giving it away in exchange for value that you need.

Put together a concise email offering a set amount of free advertising and full handholding in exchange for weekly feedback on the product and the rights to publish a case study after the campaign. Work hand in hand, get them awesome results, then create a report of what you helped them achieve and start to publish these on your site and include them in your future outreach.

Once you have proven yourself with a couple of clients, you can take those results and start pitching people on some form of test that is not free. Offer to help them manage the entire campaign and guarantee some results, but make them pay for it after you have your evidence that it works.

Getting your first few customers involves being very scrappy. Don't expect to throw some ads up and get people to signup for a paid service that's intended to replace something that works very well already. You will need to do things you normally wouldn't until you're no longer an unproven solution.