Hello Mariya,
Very nice t-shirts. I am not expert but your title should have the same tags as in the tags section being your first three the most important in the title.
They don't have to be the most generic as you will compete with too many brands.
The tags also have to be in the description, though Etsy doesn't use them google do.
On the other hand doesn't matter how good your tags are if your photos are not crisp and show the product at it's best you do not entice people to click on your product right now. Maybe if you don't have a model you could use a mock up, they are many around and they are cheap.
Also you should put 5 photos of each product.
https://www.etsy.com/listing/508925730/womens-floral-t-shirt-pink-flowers-shirt?ref=teams_postIt's a lot to take in at the beginning but if you work on the different aspects of your shop little by little soon things will come around...we've all being there...it takes time!
Hope it helps!