Someone else creates the design and physical products, correct? In that case, your main challenges are

(A) identifying customers
(B) convincing them to give you a chance
(C) keeping them happy with good customer service

When it comes to (A), you should probably be knocking on a lot of doors. You'll experience plenty of rejection, but some people will say Yes. Do a good job, and they may remain ongoing customers or refer you to others. This doesn't require any formal study of marketing. It just takes practice and long hours.

There's another way to handle (A). And you should probably be doing both in tandem. This involves studying the behavior of people you want as customers. Many people are searching online every day to find companies who provide exactly those products and services you offer. You can ensure they see you by running a pay-per-click advertising campaign in Google and other search engines. SEM professionals can help manage your expenses and ad placements.

You'll also want to evaluate the written content on your website and think about SEO. The better your websites perform online "organically", the higher they rank for all the relevant online searches, the less you'll need to pay to advertise.

I can't help you with customer service (C). But maybe I can help you think about (A) – finding customers online. And I can certainly help with (B) convincing the people you approach (or who find you on their own) that they ought to hire you.

Practicing your sales pitch is important, since you'll be delivering it to a lot of different people. But much of your sales pitch is embedded within your website and brand name. So you ought to pay very close attention to the visual and verbal quality of all your promotional material, ranging from on-site text to graphic design, verbiage in brochures and ads, and (perhaps most crucially) the domain name you've chosen to be known by.

That name / domain is everyone's first impression of you. Even before they click, they've judged you. When they arrive on the website, they see the visual layout and the written content. So even before they've tried your actual services, they've judged you again. Clearly, it's worthwhile to perfect these early stages in your sales funnel so that prospects make it all the way to the finish line – i.e. asking questions and hiring you.

If you'd like help with naming, domain procurement, branded copy writing, or SEM strategy, perhaps I can assist.

Well you've certainly got your work cut out for you if you've never done something like this before.

First - sales is a very viable option here. Since you're working with businesses who tend to high average order values (AOV) you can justify the cost of spending time hand holding potential clients to make sales.

You'll probably want to build a website and either optimize it for search engine optimization (SEO) or use content marketing to attract traffic. If you can give customers a free catalog or other sort of incentive in exchange for their email addresses you have the start of a lead generation process. You can then take those leads and contact them to get them to commit to buying.

If you have high enough margins on your items you could run pay per click (PPC) advertising for your keywords. Although if you don't know what you're doing you could blow your ad budget pretty quickly.

If you haven't done anything like this before I suggest first seeing if you can even get traction on your website. If you can't get that it's unlikely you'll be able to have enough contacts for the sales process.

I hope that helps! :)

Consider the cost (time and money) of acquiring that skill vs. hiring that skill. Often entrepreneurs try to do it all, when the best choice, and the path to sustainable growth is allocating (or raising) the funds to hire professional talent.

Hiring talent (which is often better than you could ever be, because that is their single focus, and passion) prevents you from getting bogged down in the lengthy process of acquiring new skills every time there is a need, and getting distracted from the high level strategic leadership the company needs to thrive.