You should check out Trent Kaniuga on YouTube and Gumroad. He's done a bunch of HS cards. He has a bunch of time-lapses with useful commentary and some extended videos that go through the entire process.

Thank you for letting me know! I've checked out a few of his YouTube videos and he gives some pretty solid advice.

Marc Brunet (aka, Cubebrush) Also worked at Blizzard at one point! He has very many useful tips on his Youtube Channel. I also want to work for Blizzard one day, Marc and Trent have been great help to my progress thus far. Hopefully they can help you as well.

Blizzard's artists are so inspiring! I'm working through one of Marc's tutorials at the moment, but I didn't realise he had a YouTube channel too. Thanks for letting me know.

Current work in progress:

This is where I'm at with the penguin's design. I've started working closer with references and starting to develop his personality using props.

He is in charge of many weapons and canons, and easily carries a barrel of gunpowder at all times. I'm also thinking that he should have some kind of armour - maybe shoulder pads made from the remains of old barrels.

Feedback appreciated!

One thing you can do for matching Hearthstone's style and level of execution is to check out the personal pages of your favorite card artists. A lot of HS artists show step-by-step guides on their artstation, DeviantArt, or personal pages for their card paintings.

It can also help to disassemble your favorite card art. Take it into your editor of choice and isolate just the values, just the colors, posterize it to it's core white vs black value scheme. Zoom way out until you can barely tell what it is and redraw just that little cluster of shapes. Smash it into tiny pieces and put it back together. Btw, value control seems to stand above the other art fundamentals for making great card art, lol.

I've been wrestling the the character's design a lot over the past few days, trying to find the balance between the art style and real penguin anatomy. Above I am beginning to over paint my values. At this stage he is very dark, and doesn't fit with the Hearthstone style at all. I'm trying to fix this by focusing on individual areas at a time - so far I have painted the armour (the isolated one on the right is the original). I'm looking at a lot of different card designs for colour, lighting and material reference.

At this point, I think my best option would be to sketch out some dynamic thumbnail designs for a 'card' so that I have something fresh to think about, but feedback is still very appreciated.

@frankcauthen Thanks for the suggestion! A lot more analysis is definitely needed to help with my understanding of the techniques.

Earlier today I found some of the concept art and line work for various Hearthstone cards, and used these as reference when designing my second penguin.