A small oil portrait of the character Tedros, done for Anbessa on Furaffinity.
There used to be a lot of rules on how to do official people's portraits before impressionism and the modern art era. One rule which stuck me as odd is that smiling was strongly discouraged because it could distort facial features and would make the painting tiresome to look at for a long time. It is true that smiling expressions can be annoying to look at unless the smile is very subtle (e.g. the Mona Lisa) or the whole painting is very stylized (e.g. portraits by Boldini, the impressionists, caricatures, etc.). Also telling the model to keep a neutral expression allowed him or her to relax and display their most natural attitude.
I have no idea whether this concept may apply to anthro characters. After all there is no real model to copy from and many animal muzzles don't look very expressive to untrained eyes, especially when they sport a neutral expression. But it's an interesting challenge because neutral expressions are always hard to draw convincingly, it's easy to make them look dull or silly.
Even if you draw a realistic anthro muzzle, the most straightforward way of making it expressive is to map cartoon expressions like these onto its features:
This kind of "standard" expressions can actually be applied to anything (animals, objects, etc.) as long as it has the equivalent of a mouth, two eyes with visible white and a discernible pupil (so we can understand where the gaze is pointing) and very mobile eyebrows. A lot of RL animals look like they have no expression just because the white of their eyes is not visible and they have no facial features similar to eyebrows, while animals like cats and blue-eyed huskies feel very expressive because they have both.
I often abuse eyebrows to exaggerate expressions in my pictures and I know sometimes I'm guilty of stepping into the 'TUDE eyebrows minefield. So in this picture I downplayed eyebrows a lot (though the dark patterns around the eyes work fine as proxies) and I tried to keep a neutral expression. I'm quite pleased with the result. Now I have a few other ideas to test in small portraits like this one...