USE ALL OF THE SECURE PAYMENT METHODS POSSIBLE!
Are you invoicing for orders or are you using a website? Do you know what payment channels are available to you? Do you know what payment processors your customers prefer?
I often hear business owners say "I don't use xyz because their fees are higher than xyz", but I challenge you to ask yourself, "is not using xyz actually causing me to lose sales that I would have otherwise made?"
If you ask your customers you may be surprised to find out the answer to that question is YES.
For a long time I didn't have PayPal implemented because their fees were higher than Shopify Pay. Then I asked my customers what they thought about PayPal and an astonishing number of people said they were hesitant to purchase because I didn't use PayPal and many others said they always had the intent to purchase but never did because their credit card wasn't easy to access and I didn't accept PayPal, which is much easier to access online. So I setup PayPal and my sales increased by more than 30% in the first two weeks.
I missed out on a large volume of sales because I was more concerned about having to pay a few cents more per transaction than what I would have paid through Shopify Pay. Stupid.
Don't let the reason you are not getting sales be because you aren't accepting money they way they want to pay (NOT REFERRING TO UNSECURED-UNPROTECTED PAYMENT METHODS SUCH AS CASH APP, FB PAY, ETC).