Tbh, it's largely just a matter of practice. :'D The reason our styles tend to be inconsistent at the beginning is because we're still trying to figure out the 'right' way we want to express things on the page, like faces, hair, basically anything.
As we get more used to how we like to represent certain things in our art, the more we solidify our style.
Personally, the first two pages of my comic, I literally drew half in vectors since I couldn't figure out what I wanted them to look like (or how to get the look I wanted \D).
Thankfully, I'm getting better, but I'm still pretty far from having 'consistent art'. You just gotta bear through it, and keep in mind the proportions you want for your characters. Use a reference/model sheet if you have to~
Good luck~~