hey aria! i'm here with your crit! so sorry it took me ages omg D:
firstly, i do want to say that i think you are too harsh on yourself! i definitely really like your style, and you're a fellow staffie, so there's not that much wrong here, and definitely not so many issues as you think you have <3 don't be so hard on yourself.
i am going to use three of your banners to illustrate what i think your main problems are atm. [this] has really cool composition, but see how saturated the greens have become? it's not quite neon and makes the whole banner really quite LQ. on top of that, the oversharpening makes it look more LQ again (with the text affected too) and this is a case of too much negative space, if that makes sense. if you compare it to [this], which i love, the people are still easily visible and the composition is still quirky and bright without things going overboard.
now let's look at [this]. love the comp of the squares and things, but again, the people get too small. you have to balance between negative space and visibility, and sharpening a lot to make their features distinct will just bring image quality down. you also put a lot of textures in darken, and this is evident in a lot of your other graphics, but imo that usually doesn't do much for the graphic. it works where you have the six squares with the little guy, but on the left hand of the banner, it just obscures his face and the colouring is too saturated for it. in [this] banner, too, i didn't even realise that there were people on the very left and right because they were set on darken--it took a third once-over to find them. definitely remove [this], btw. it's rather dark, sharp and the textures on darken, once again, don't quite work.
and then in the banner [here], because you've spread out your images so much, there is no focal point. in the previous two banners, there was a focus and the images were stacked in a way across the banner that there was a specific place that i went to. here, jenna is in so many places and composed in a way that my eyes roam. scaling it back occasionally will help you, i think. [this] is absolutely gorgeous, and it's got just enough negative space, simplicity and is still very you!
honestly, there's not much wrong with your style you just have to work on some minor things and trust your instincts; when something feels like it is enough, then just step back and let it go. watch for oversharpening, too much negative space and blending on darken. if you just keep those things in mind, you'll get to where you want to be <333
[this] is incredible, btw!! gorgeous colouring, soft, great composition - i think you'll be able to translate more of this into banners/sigs.
i hope i wasn't too harsh and i was able to help! please let me know if you have any questions or comments, or if there's anything else i can do for you!