Grow sales in Etsy shop

I want to make the sells grow in my shops and this is general point, how this possible to make for me is not important.

Any work which convert to real sales, other things is not interesting.
I have the different shops more than year, i not a newbie in that field,
i have the sales but i want the big grow of sales not the few more sold items like usually !

Items
1. Wedding digital printables;
2. Birthday and different event invitation by phone and printables
3. Wedding Face Masks with my designs
4. Mugs with different my designed images
5. T-shirts with my designed images

The services what i want , in the best way, can be like administartor who keep the eye month after month for the some basic fixed price + % from sales
or
you can offer your ideas about the this case.
I have the 4 Etsy shops and 1 Shopify shop