I have a lot on basic form, shape, foreshortening, and other general tutorials that might help you with some more complex drawings.
Sycra on youtube has a lot of amazing tutorials like this one on foreshortening and this one on how to make plain poses look less static and more fluid and interesting. Not to mention hands and feet which are my personal hell so they've been really helpful.
There's also this cool video I found on the basics of light and shadow and this for if you want something a little more complex. If you're tired of all my videos, theres this article on how different techniques for shading can affect how your image looks.
For coloring, there's this little article on how to create a color palette and this explanation of basic color theory.
This has both videos on explanations on patterns and textures.
And if you need to practice, here's a cool list of exercises to try.
Something that also really helps me is just watching speed paints, I try to pay attention to how they shade, what colors they use to accentuate other colors for light/dark, how they draw their faces and proportion the spacing of their eyes/etc. Things like that. If you want, here's three different cool speed paints that I like.
1 (This one is good for an example of someone coloring, you can see on the side that when they're shading they're not just going up and down but how they move the color wheel itself left to right in order to use different colors to shade.)
2 (The expressions here are really good and also you can see how they layer the hair and make it look fluid when drawing.)
3 (The style here is stunning, and it actually shows the artist's process beginning to end which is cool.)
Good luck! I hope at least some of these help!