There's really no simple and easy way. The best way is to invest a ton of time and work into it. Anyone who is good will attest that nobody started out good, and nobody became good immediately. Everyone who is good got that way by investing a lot of work into practicing to become so.
Practice life drawing of actual models (or photos) to get the basics. This is something a lot of people hate doing, but it's really important. It helps you learn basic anatomy, structure, and three dimensional volume, and a number of other things you can't learn from the next step. Anatomy and facial structure tutorials are also helpful.
Pick out your favorite artists and copy their drawings freehand- not trace. Try drawing the exact same images the exact same way. Doing so will help you dissect their style and figure out what exactly it is about their work that makes you like it, providing a foundation for your own style.
After copying an image exactly, do it again but different. Change the pose a bit. Change the angle. Make the image your own. This will help you develop more senses for drawing something original from scratch.
Do rough sketches that are completely original, entirely from your imagination. They will look shit. Try to figure out why.
You won't be able to do it yourself. Share your works. Accept criticism. Find people better than you who can correct your work. This is probably the most difficult step. Sharing something you think is terrible. Having something you think is pretty good criticized and called awful. It's extremely difficult, but also the only way to learn what you're doing wrong and fix those problems. Because there are a lot of things you won't notice yourself.
Watch how other people draw. Especially people better than you. You'll learn new techniques you wouldn't have discovered otherwise. Look for rough sketches they've done. Look for rough drafts of finished works. Look for videos showing their whole process.
Practice every day. Without fail. Draw something of some sort every day. If possible, dedicate an hour a day, at the bare minimum.
Finally, this is not a step-by-step list. You should be doing all of these things. That doesn't mean doing every single one of those things every time you practice. But you also shouldn't be exclusively doing one of them and neglect all the others. The proportion of time you dedicated to each can be modified depending on what is more important at the current time, but they need to all be touched on occasionally.
And that's just how to practice and learn. Getting into techniques would be another lecture entirely.