What's the good method of zero-based self-study sketch?

I began to learn painting at the beginning of this year. I am also a zero-based person, and I have no talent at all. I still belong to the kind of person who can draw straight lines.

I bought a bunch of oil paints at first, but the technology was really limited and I wasted a lot of time. Later, I bought a notebook and a pencil myself, and spent the most interesting things in my life every day, starting with the most basic stick figure. And drawing your own life will be more interesting and you can stick to it. So you can copy first and find some interesting materials.

I have been painting for more than a month, but I can still draw some very simple things. The most important thing is persistence, otherwise everything will be in vain.