Your question says painting, but your details say drawing. Drawing does come first. There are books and videos that can help, but nothing beats in-person instruction.

And practice is the most important thing.

I’m an artist and I’ve found that I’ve progressed the most when I’ve found teachers and studios that I can learn from. Like looking for a good therapist, it can take some time to find one that works for you.

There is a book that’s very popular called Drawing on the Right Side of the Brain by Betty Edwards. I haven’t used it myself but it is a classic and there are online workshops that are associated with the method.

As with anything you want to master, daily practice is a big help. (Not that I do it anymore but it does help.) You can get a small sketchbook and carry it with you everywhere.)

Oil paints are really great because they’re so forgiving. If you mess up, you can just let it dry and paint over your screw up, building up texture. A lot can be gained from copying other artists—seeing how they work with color and how they produce light/shadow. It’s much more complicated than just tinting colors lighter-darker.

I’m not a real painter by any stretch, but my mom is and I’ve done some painting with her.

I recommend drawing real objects instead of from images. If you must work from photos, try taking them yourself.