Honestly, the amount of 'draw like a pro in 30 days' stuff out there is overwhelming. I wasted so much time jumping between random YouTube tutorials before I figured out a method. The single biggest thing that worked for me was focusing on the 3D shapes underneath everything first. Forget the eyes and hair for a minute. Just draw the head as a sphere, the torso as a box, the limbs as cylinders, over and over from every angle you can think of. It sounds boring, but when you later sketch the actual character on top of that armature, it stops looking flat and stiff instantly.
Once the basic forms felt comfortable, I moved on to gesture. I'd find manga panels I loved and spend 10 minutes just doing super quick, messy scribbles trying to capture the energy of the pose, not the details. That loosened up my linework a ton. Then it was a matter of layering on the 'rules'—proportions, facial feature placement, how hair flows from the scalp. I still have a sketchbook just for hands and feet, they're their own whole nightmare.
My advice is to pick one specific style you adore and really study it instead of trying to blend five different ones. I stuck with the clean look of CLAMP's earlier work in 'Cardcaptor Sakura' for ages before branching out. It gave me a solid foundation to understand why things look the way they do.