Need advice to increase conversions on website

I'm an artist/designer and need advice to increase my conversions on my print on demand website. If you have time, please check out my site and critique it so I can refine it for higher conversions. I find pop ups to be spammy so I didn't include it for e-mail, but I'm second guessing that decision because everyone usually advises to have pop ups. Also, if you have any additional suggestions, I would be eternally grateful to hear your input. Thank you!