very general and unspecific advice, but 'just draw'. I used to be in the exact same boat as well. only animals. not even anthros actually, so you're definitely better already than I was.
draw the human face regularly. practice it. by looking at other art or real photos. that's how I did it. especially artwork that was close to what I wanted to achieve helped me most compared to anything else. If you can roughly imagine what you want it to look like, try to stick to it, and practice that over and over, until it burns into your brain. it took me several years. Doesn't mean you will take as long, but don't set your expectations too high. Learning a different kind of face proportion can be challenging until you get the hang on it. the human face isn't the easiest imo. take your time.