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.