Need advice on scaling small ecom business

I have a very small online business in which I started in November 2024. I sell made to order, customised watches. In the last month I’ve sold about £1400 worth, averaging about 2-3 orders a week. At the moment, I’m only selling on eBay, as I have a good account with good feedback, this results in shorter payouts which massively help with cash flow.

I am looking for any advice as to how I could increase my sales. (I live and sell in the UK). There are other people selling similar things as I haven’t really invented anything and I’m not entirely sure how big my market is or how to promote my watches but I’m willing to try anything. Any advice would be hugely appreciated. Cheers!