I like your welcome message. But I also like your slogan and think it expresses your brand. Maybe you can find a way to work it in.
I use canva for logos, banners and avatars.
https://www.canva.comIt's free and easier than other graphic programs. They have presized templates for etsy banners, Facebook pages, etc. that really helps me get the sizes right.
Photos are such a big challenge. I'm still working on that. One thing that is helping me is taking a good look at shops that sell a similar product to mine. How do they stage their photos, write their descriptions, tag and title?
Sometimes I make treasuries to educate myself about my target market. But I also use treasuries to study my competition. These I keep private. If you go to my ptofile and scroll down you can see how I looked at how etsy sellers use buttons in their products. Maybe you could make a treasury as a way to study how t shirts are photographed effectively. It's a fun way to learn.