you have some very solid, beautiful looking designs! one thing I notice though (and that's pretty much the only thing) is when you design wings, the colors seem cut off. for example in your 3rd design and in a few others in your design tab. A few of them have nice transitions from body to wing, but a few seem "separated" because of the harsh difference in contrast. maybe you could work in a more gentle transition from one to the other (with pattern, or a gradient)
I know I'm technically improving as time goes on just from experience, but I'm just wondering if there's anything I could be doing, or anything I should focus on specifically. Here are three of my most recent designs, and you can see more here if you'd like. I just really want to work hard and improve this year, but I don't know what steps I can take to do that - I hope that makes sense!
I don't do pony designs, (ooh, bad start already), but I think most creating rules applies to horses too. You know like: nice pallette, sticking to one-two theme, the more details the more people will think it's an 'expensive' character, and of course "original" ideas.
Maybe saddle and other stable equipments are expections. Style that to the pony and you'll might get an even cooler look.
i really like the shapes in your designs! the art is clean, they're not overwhelming with details, but they look pretty unique with the touches (like antlers and patterns) that are added to them.
but i think you might have fun trying to play with other palettes; they're all mostly soft pastels + neutral colors (white, gray, black, some browns) with maybe a pop of color, so trying to balance palettes outside of your comfort zone (like tilly melon's palette) might be exciting!
you could also try to add more accessories - hats, clothes, glasses, jewelry - and try to balance those with both plain- and heavily-patterned ponies. for a pony with an elaborate pattern on the back and a hat on the head, the legs will probably feel a bit bare. do you want that, or should you add some sort of detailing to the legs to balance that out? sort of thing