Flowery Princess Swordswomen

• Despite the fact that this particular piece does not have any sort of defined lines, I can tell you have your ways of making them look steady whether you use a pen tool or just have very good pulse.
• I love how you took your time to detail the armor plates on their limbs and how you did your homework when it came to how they're actually supposed to look.
  
• However I think you could've added a couple extra lines to give mo details to certain elements, like the hair of the blonde knight, the handle of both swords, a line right between the edges of the blades to give them some depth and make them less 2-d and some fold on their clothes to make them look less bland and some extra lines for the skirt of the one on the right.

Color: good!

• My first guess here is that you tried to go for a minimalistic style, just flat vibrant colors and a dark background to make them stand out
• None of the colors feel too off or too strong to create any sort of issue to me so you did a good job on that!

Anatomy: very good!

• The proportions for both characters look okay, each of their limbs appear to have the correct length and their poses look somewhat believable (which is something I'll talk about later on).
• Nevertheless, the shape of their heads, hands, and feet look very nice! which is something people always struggle with, good job!
  

Posing: bad/needs more thought

• However I have to say that the way they appear in the picture looks kind of... stiff and emotionless, the one on the left doesn't look like she's charging to battle despite having such a menacing stance, while the one on the right is... jumping? away from the battle?
• (Right knight)Allow me to elaborate on the last point, while the girl on the right looks like she's about to swipe the sword against her opponent her hair is going in the complete opposite direction! something that is really off putting in this situation, in addition to that (and this one is a personal point of view), her torso doesn't look turned around enough for her to actually attack on the air, so it almost looks like she's actually falling on her back.
• Also, the way she's holding her shield (Im assuming that's her shield) so close to her chest in midair looks unconfortable and weird to me, and the fact that there's no shading or any extra detail makes it look even weirder.
• In addition to the point above, her sword leaves me completely baffled, the overall design looks very fantasy like but also extremely uneffective, at first I thought it was just really long but going farther into the distance, and the but the position of the hand grabbing the handle tells me that's its actual length.
  
• (Left knight)Following on the one on the left, the blonde hair waving in the air and her green skirt going in the same direction plus the way her legs are positioned tells us that she is running, but the feet being relatively close to each other and to the ground as well plus the almost vertical torso which is not leaning forward tells us otherwise.
• As a small side note, I think the way she's holding her sword is a little awkward, that is not a convenient pose for a slash and doesn't look to efective when stabbing if you ask me, also considering that they're both already really close, I don't think  she will be able to attack properly when they clash.
• I also noticed none of them have ears, or at least I can't seem to spot them.

Shading: non aplicable/try adding some

• I can't really say anything about shading because there's none, but I think you should add it in these type of drawings because they help turning 2d objects into more 3d-like ones, some shading could've added a lot more depth to the characters and make them look less bland overall, as well as it could've fixed the inconsistencies regarding the swords and the shield of the one on the right.
• Also, shading and/or lightning is important when it comes to armor because it can help to state what material are they made of, in this case some shading could have added some shining to the armor plates to make them look like actual armor.
  

Background: Averange

• I'm sure you already have a bunch of ideas as to what bg to make for this, but if I can suggest you something, try going for a more neutral color next time, or maybe use some gradient effects because I think the pitch blackness of the bg makes it harder to appreciate the knight on the right, not only because of her armor but because of her skintone and hair.
• If you want a suggestion for the bg, I'd say you add a couple more soldiers charging in the background, and a battleground with shot arrows, smoke, some bodies here and there and some soldiers already fighting

Conclusion:
I like the extra touches to the armor of both knights, I like the colors chosen and the overal design of their clothes
But the overall picture seems devoid of life and uninteresting overall, the faces of both characters hardly have any difference with each other and I don't think they reflect their actual feelings, their poses look stiff and sort of uninteresting, and the lack of background doesnt add anything else to the picture.

But I can see you're putting effort into it and that's what it matters, I may not be too fond of this piece but I'm sure with time you'll create one that will leave me speechless, (and everyone else too)


I hope this can be of some use to you in anyway
Have a nice day