Online clothing is hard, what backstory offered is a good start but seo/sem only will work in a niche where people search using google and there is realistic competition like specializing in a specific kind of shirt that few people offer. If you’re doing fashion, you need to build a brand. You’re going to get the most traction with social: Specifically Facebook, Pinterest, and Instagram. The rest is about publicity, getting recognized and hustling in more of a PR kind of way. There are opportunities to do contests with some brands like beta brand but ultimately, you just have to hustle till you get recognized and the promotion machine and echo chamber of fashion bloggers gets you out there.
Start to follow other up and coming fashion people, especially in your city and learn what they are doing that is working. Get yourself into a higher end store, do some pop ups and promos at style oriented events, and make sure everyone knows what you’re about.
On the business side check out SBA and score, and start attending every fashion show, textiles show, and anything else that you can in the space. Meetup might even have some stuff in your area. Get square or another startup friendly point of sale, register your business license with the state so you can file sales tax if that applies to any of your products. You can file an EIN as a sole proprietor or do a legalzoom s-Corp or llc. Open a business bank account and keep it all separate. Get quickbooks online and manage your expenses. Start looking for places to make the stuff you’ve designed or start networking with designers. Business is about coming up with all of the steps and putting it all together. Ultimately I think it’s about immersion, learning, and not getting stuck by neglecting some part of the business. If you can find people already doing it well but with different products or designs you can hack the learning curve. A partner might also be a good option but they have to be strong at what your week at and vs versa. Otherwise you won’t get the 1+1=3 scenario and I think that is what is required for a good partnership. One person tends to have more vision, product, sales focus and the other might be really good at logistics, operations, finance, supply chain, etc...