SLTL, since you asked. I have been through way too many critiques in school and through my professional life to not give my honest opinion. It doesn't help anyone to give anything other. There is a difference between constructive and destructive. I would never give the latter as you probably know already.
I really liked your owl. The detail in the wings is nice. You need the same amount of detail in the face --it looks unfinished. Contrast-black to white with medium tones. The owl face is mosly medium tones. Pull it out with black. Owls eyes are usually piercing, check them out with a reference.
Since I started with horses, my love as a child, I recognize good construction and above all else you definitely have a talent showing with the Arabian. (also my favorite breed) Same contrast, detail issues. Check anatomy books for horses for underlying bone, muscle structure. The eye is the most important on the Arabian. They have deep, strong eyes, not much white showing. Should have a highlight white if nothing else, but there are medium tones too. I love the Arabs that have alot of black around their eyes. I went to an Arabian farm earlier this year and wanted my sketchbook but had no time. I should go back as I was invited.
The Appaloosa. That's a great pose. The overall structure isn't in the right proportion. The underlying anatomy isn't correct. Don't worry ever about detail until you have that right. Legs even though they are in grass have to be indicated--the line carries through the grass. Each drawing has to have weight showing. Does it look like each leg/foot on the ground carries its share of the weight? Or does it look like it is in the air? If you don't put the black shadows in the right spot or get too heavy (belly) on the black it looks "cut".. too hard. The part of the horse closest to the viewer is lighter, a lighter border edge, the edge away is black, heavier. I used to copy alot of horse illustrators when I was a kid. Then I moved on to photos, then my own photos and then real life. Even though an Appy is spotted, their spots are sometimes muted by the light. Always remember the light. If alot of light, shadows are light like on the inside of a leg. If the source of the light is a bright light in a dark barn, there is severe shadows so detail is lost...somewhat like the Appy drawing. Seen during a thunderstorm, lightning the light source, would cast the horse in deep shadows, the white of their back also a medium gray. The direct part of their face hit by the brightness of the lightning only would be light. The details of the spots would be barely indicated.
The lioness is pretty good so far, again needs more work, detail, contrast, perhaps to show weight, grass underneath, with shadowing. What part is in the light? What do you want the eye to draw to first-her eye or to her cub if that was in the picture? Or to contract her to lush folliage of the surroundings? Is everything recognizable in the picture?
The best way to plan a drawing. Remember the whole page, use the white space, where is the focal point. Draw light to get proportion, then slowly build up lines. As you draw more, your line gets more sure in the stroke. Before it is detailed plan the light and the degree of shading. Sketch in shading lightly before details.
PS, I like realistic drawing as well. Tess's style is stylized which is fun too.
MACaver is realistic as well. If anyone else wants my comments, you will need to ask... as Tess and Pam has done. TW