I'm on the course myself, and I'm no expert but can critique the painting about what little I know so I hope it help! (Even if it's and old post, but please don't take any offense it's just my opinion and we're both learning, so I know how it feels xD!)
I can make out the volumes well in the Aeldari, but I feel there's a little too much weight/mass in the heavy shading (it makes it a little difficult to differentiate from the camo pattern you're going for on the wrists and arms, and I feel you could do a little more to define the points that separate the wraithbone and fabric a little more with a sharper contrast).
I feel like some sharper values to bring out the lighter tones would be good as well, and the use of negative space is established well in setting the Aeldari Banshee apart. It gives me enough resting space for viewing (although I feel the noise in the background with the established shapes just a tiny bit disrupts that, however I love them as I'm fond of battleground artwork myself so I'm pretty sure thats what you were going for).
Under the Aeldari's arm though, the rocks feel too dominant; my eyes feel drawn there, the arch of the arm itself creating an implied line. I feel like you could push the trees back a little, pay a little less attention to the rocks as well, and that might improve the focus.
Some parts of the armor lose a bit of its volume (which brings me back to the mass represented by the values of the colors), but otherwise going back on that, it's pretty sound. I like it
So to break it down,
—The spacing looks fine! (Like always with us beginners, or well, me being a beginner, there's always room for improvement. I'd try to push the boundaries of the trees out a little bit so it's not as 'compact' (just a tiny bit), and make the background a little less cluttered unless - again - that was your intent, being Warhammer 40k and all :D)
—The grass and rock under the arm feel a little too 'heavy' (as mentioned, they keep drawing attention when the Aeldari is the focus)
—Try using a lighter tone for the shade, as it makes the armor seem flat and lose volume in certain areas; however, it's pretty good otherwise
—Adding to the above point, try adding some sharper tones - light or darker - to help distinguish points on the armor a little more.
It seemed like I was nitpicking to be honest but, I hope it helps, it's a pretty good piece for what you were trying to do. Heaven knows, you're still ahead of me lol ![:blush: :blush:](https://d1f4appuj81sj4.cloudfront.net//images/emoji/emoji_one/blush.png?v=0)