The book Magickal Riches has a talisman for increasing sales. I haven’t used that one, but I’ve used a couple of the other talismans (the Master Money Talisman, the one for Buying and Selling, and the Secret Source of Money Talisman) and the genius rituals with good results.
You’ll want to think of this as a long-term project. You may get results immediately, but it could also take a bit for the full effects of the ritual to be expressed. Someone else mentioned that having good marketing copy would help. The magick will influence factors beyond yourself, but it will also guide you to make changes like this that will help your sales.
In case you don’t pick up the book (which I highly recommend for the ideas, even if you don’t use the magick), one of the key insights it shares is that focusing on the emotions rather than the money often improves the magick. Instead of thinking about how much you want your sales to grow or how much more money you want, you think about the feelings that money could bring you. You don’t focus on the cash, but on the things you could buy, the places you could go, and the experiences you could have and how all this makes you feel.
If you do work with the book, I would trust that it can help with your current business, but would also remain open to new ideas and possibilities. From my experience, the magick will sometimes work by revealing a different way of working that has the potential to be more profitable in the long-run. Some businesses and industries are just more lucrative than others. This magick isn’t as disruptive as the book Wealth Magick by the same author, but it will sometimes work in a similar way. That may sound like a pain, but in the long-term it will save you a lot of time and effort and make you a lot more money.