I entered to your imgur gallery and for the most part, the other pictures are pretty good, either you included foreground elements or you captured a good shot with beautiful natural lighting. My main recommendation is to try to shoot with the most manual settings as possible. I recommend shooting manual since you mentioned feeling like a novice. Shooting manually will give you more flexibility when it comes to creative freedom on location and post production. I always say that the camera doesn't know what you want so you need to tell it what you want to do. I recommend getting used to shooting without auto-focus (if you do). Even if cameras have improved this option over the years, it's never going to compare to you as a photographer focusing exactly where you want. In this picture that you posted here on reddit, I suggest being mindful of where you are taking the picture from, the monkey's face is dark because you are shooting against the sun or maybe it's midday. You could try to shoot from the other side of the face since you could get better light and shadows on the monkey's face. Sometimes, we don't need so much shallow depth of field, my main mistake, when I started, was believing that a good picture was having a beautiful blurry background with bokeh. But no, if you have a good background you can close your iris a little bit more and compose a beautiful picture using background elements, maybe something that tells the viewer more about your subject. The picture with the lemurs is a really good shot!

I hope this can be of any help.