Tone and Target Audience are how I decide my art style be, and it has to based on projects.
Though I tend to draw more cutesy things and have never done a mature rated stuff.
I did have some other art styles before my comic series.
Without any other webcomic I have, so i use my game art instead, 'kay?...
This one's is a family friendly cooking game. Artstyle & promotional arts looks clean & semi-cartoony.
Here's another game with opening screen/end screen art, This one is pixel-art oriented.


Overall because the games are family friendly, they're in the CUTE side (with larger heads) , with saturated color.
I drew some clean furry arts some years ago but now I don't do them anymore (all passion now went to my comic). This one doesn't have target audience and i draw whatever i like to draw, sometimes experimenting styles. It ranges from drawing more realistic bodies, to something cutesy or 'Sonic' inspired.
Back on my current webcomic, My target audience is young teenagers (and furry lovers), because of the story of a young teenage cat boy. It features semi-cartoonish animal people, but it has a dramatic tone underneath the peaceful setting to the story. (even if it doesn't show recently) So my art decision is to design a mix of cartoonish side characters and more manga-like main characters (that able to do emotions better)
Art direction can go different ways for different artists. I'm just very influenced by b&w mangas and want to create that manga look. (the formatting is only a bit different) Well, drawing traditionally is part of a style, the uneven organic lines work nicely on my fantasy countryside settings, so it's a huge plus. Oh I wish i can keep inking tranditionally until the end!
That's all, folks!