How do I stop my digital paintings from being muddy and what should I work on for my painting skills
Hey guys so often my digital paintings particularly their values are described as being muddy. I want to rectify this but I have no clue as to what resources would be best to learn from. Does anyone here have a recommendation as to any sites or texts which cover understanding and improving ones use of value. I hope this isn't a stupid question to ask btw. I've just attached one of my paintings below just as an example of where I am basically at when it comes to digital painting
Anyway thank you in advance.

Replies
Here is what I did super quick color picking the colors you already have in your image:
Animated form:
You can see how small refinements make all the difference
Check out this page, it is very information dense about painting: https://androidarts.com/art_tut.htm
Best of luck!
If you havnt, check out this tutorial! (scroll down some to get to the content).
its not focused on anything in particular, but covers pretty much everything you need to know to level up to that next step.
EDIT: lol! realized that I linked the same tutorial as @Alemja did, I guess its just that awesome of a tutorial
Muddy colours can be avoided if you pick colours diagonally instead of vertical/horizontally from the colour box(in Photoshop).
Previously I have done some directions on how to make colour appear to be more natural & non muddy, kindly see the attached:
To support this theory, you can do some test by open a photo in photoshop and pick the areas where it transition from light to dark.
Hope these helps.
Being kind of self-taught on this matter, I understand that there are a lot of different resources online, these are what helped me:
Scott Robertson - How to render (Gnomon DVD) ~ Scott Robertson teaches you a formula to understand how black and white value shading works on a certain object with a certain light. It is extremly important to be able to understand this formula he teaches in the DVD to be able to render stuff well, no matter how pretty your colors are.
Pratical Light and Color by Jeremy Vickery (Gnomon DVD) ~ Just overall absurdly excellent DVD, Jeremy is a Pixar artist, he teaches the same stuff Julianimator mentions to pick colors correctly and more! If you watch these two DVD's a few times and practice what's in them, you won't need any other resource. If you don't believe me, ask any Naughty Dog artist, this was their resource for Last of Us lighting.
A lot of teachers and artists have their own way of picking colors, you'll find many different theories, but they are just theories. Color theory itself, the one they teach at schools, was invented less than 100 years ago, so it is normal to be confused about this topic. The way I see it, it's a growing matter.
Edit: it's important to note, you shouldn't work by formula too, there are certain exceptions in nature. I recommend doing a few material studies before you venture into painting something, it's the way many professional artists work. It's not wise to want to discard that step.