1. Make it not cost more to me. I don’t care what your costs are, but I do care what mine are. If I find my way to your shop and have my wallet open, that’s the time to be cost-competitive, not to tack on a $7.95 shipping and processing fee (unless your product price is $8 less).
2. Give reasonable assurance that customer care, if needed, will be about as accommodating as A2Z.
3. Give reasonable payment options. Some people want PayPal. Others hate them. Personally, in part because of #2, I often use them.