I painted a character from my graphic novel but not happy with it, could I get some opinions please?

You have a good sense of color and design, but you need help with anatomy and perspective.

There are a TON of good books out there, but I'd also suggest reading some of the masters of the form:

Russ Manning

Dave Stevens (who apprenticed with Manning)

Steve Rude

https://store.3dtotal.com/products/beginners-guide-to-comic-art-characters

Fellow artist here! I love the colors! I second brushing up on your anatomy, but I also wanted to recommend plastic artist models. Like gray scale action figures of poeple, but proportionly correct. I use them all the time. Get a stick for a prop sword and your good to go. Really helps me rough out a pose and make sure the prop/object is being handled naturally.

Which brings me to my next point, pose. Even standing still like this you can give your charters a sense of self and personality. Look for a dynamic action in the hands. Figure out which leg is taking weight and which isn't.

Have you ever spotted one of your friends from some distance away? You couldn't see their face but you knew it was them becuase of how they were standing, how they carried themselves. Same idea.

One of the things that helped me was gesture drawings, no details just motion. I would grab a sketch book and head to a park with lots of poeple and free sketch. Also get some books on animation! Sorry I have written a novel here but I LOVE art and have been painting my whole life! Keep going! I can see the skill in your work. Hell your probably better at clothing than I am! (I have to get mad reference for clothing, especially shoes.)

Not bad! I'm guessing he's some kind of water-related hero? :)

I think there's some problems with perspective. With the angle of the sword hilt, I feel like it looks like the sword should be stabbing into his shoulder rather than resting on it. I'm also a bit confused about the shoulder pads - maybe I don't understand how they should look but wouldn't the sigil with the trident point upwards? That's what I'd expect from a shoulder pad. Would you see it like that from this perspective?

There's also missing a light source. With his pose, it might make sense to have the light coming from the left (or where he's looking) to illuminate his face and left side more than the right. The lighting is flat as is.

Keep at it, I'm sure you can figure those things out if you practice. :)

https://lemmy.world/c/artshare would be a better place to share your art.

I am not an artist so can't really give any useful advice. Maybe work on the hands and improve the lips shape and make them bit smaller. Otherwise, it looks nice.

One advice from Japanese manga industry that might be relevant is that character must be recognizable from silhouette only.

Looks like a seventh grader with divorcing parents drew it.