Art is what draws me in, but character/story is what makes me stay.
1) ART - I tend to follow a series where I can observe the art in order to learn something from it (eg: anatomy, colouring/shading, expression, composition, layout, etc), or I'm just into the style. Simple doodles with a nice palette always have a place in my heart haha. It's also easier to get attached to a character quickly if I like how they look or they have a nice design.
2) CHARACTER - Same as OP, I need to care about the character in order to be interested in what happens to them. If they're just blank pawns and plot devices used to move the story forward then I don't last very long, even if the concept is fresh and the plot is well-written. Characters that are interesting, funny, cute, relatable, or provide an enlightening POV are great !
3) STORY - Character-driven plots are easier for me to consume than plot-driven ones, just because heavy lore and world-building can be hard to digest sometimes. I can follow a plot-less comic for a pretty long time as long as the character interactions (dialogue/chemistry) are consistently enjoyable. But as soon as it feels repetitive and there's no meaningful development, I start to fall behind on updates.