The only way to get good is to draw constantly. If youre not doing it everyday you're not trying hard enough.
Practice drawing from real life first before you do anime/cartoons, you need to learn proper anatomy and how lights and shadows work before you can stylize it nicely. You gotta know the rules before you break them.
Watch streams to pick up how other artists do it, seeing someone work on something can really help.
Look at small tutorials artists post like how to draw eyes, how to cell shade, how to color hair, etc. Anytime you see a tutorial like that save it and have it for reference, they can be really great, especially for beginners.I have a little folder categorized with a bunch of them, so if i need some inspiration for drawing some nice eyes I go to my Tutorials>Human Body>Head>eyes folder and look at them.
Always ask for critical feedback and always take it to heart, you will need get rid of your pride and let people nit pick every little problem in youre drawing and its your job to work on it. Dont be one of those artists who say they dont care what others think because they dont ever lose their bad habits. I always prefer getting critical feedback or someone saying something is off about my art over praise because I now have something to focus on for next time.
When it comes to drawing people and pin ups I reeaaally want you to look into: Composition, gesture drawing, line of action. These are things a lot of new artists don't know how to use but are vital for making a drawing look nice. I have some trouble with these myself so and try to make use of them anytime I can because they can really make an image go from good to amazing
But if you're just starting off do some studies, draw like 20 human bodies in different poses, than do 20 hands, then 20 feet, 20 faces, 20 eyes, etc.
Heres 2 youtubers that are really handy for people who are starting out, I highly recommend them
www.youtube.com/user/Sycrawww.youtube.com/user/ProkoTVThats all I got for now, I may not be the best artist but I think I at least know how to help someone who can't draw get gud.
If you got anymore questions I'm always willing to answer.