I've tried looking at other accounts, but they tend to use mostly generic hashtags such as #art. How do you find ones where you're more likely to be noticed?
I'd recommend defining what type of art you are seeking to find on Instagram. For example, optical art is a specific type of art. After some searching on Instagram, I was able to find #opart, which focuses on this particular type of artwork.
To become more noticed on Instagram, I'd recommend finding a niche. Instead of creating an Instagram account about art, a better strategy would be to create an account about a specific type of art such as optical illusion artwork.
The more specific you are about your niche, the better you are positioned to grow on the Instagram platform.