Hi, Norbert- what a beautiful shop! I love your work, really gorgeous.
I am a new shop myself so my suggestions do not have a great deal of experience behind them. I think you might emphasize the quality of your work, and do not do a sale- also, your prices seem low for the quality of your work. I am not sure having lower prices is a good thing- if people equate quality with price, having higher prices suggests higher quality. I do not look for sale prices with art.
Also, I think your images would be really well received printed on fabric, pillows for the living room, fabric for quilters, tee shirts, mugs and cards, etc- so many ways to do that, either by doing the printing and shipping the item yourself, or selling a digital image that people can have printed on the item of their choice- that would give you a range of priced items, from inexpensive (cards) to the higher prices items.
It took me six months to get the first 20 sales. I felt very desperate I was doing something wrong! But it just took time. Your work is lovely and I am sure your shop will do well- I really love the banner- the abstract painting. I'm a big fan of the abstract expressionists and I love the way you use color. Especially during winter I am drawn to color. Good luck with your shop!