I wrote part of this out for Jello then realized it may be of some use to others as well. This is pretty basic but feel free to ask questions about anything I don't cover.
It's worth noting I use Photoshop and a Wacom Bamboo tablet.
Once I have selected the stock and have everything resized and pasted to the blank file I use "smart sharpen" on the horse layer. I usually do anywhere from 30-50%. Then I cut out the horse and do any re-coloring I need.
To cut out the horse I use the eraser tool, usually around 6-9 px.
For adding white markings I select the desired area, brighten x150 in brightness/contrast, de-saturate x50 in hue/saturation, and then brighten again until it looks about right (sometimes certain areas require more de-saturation than others).
Next, I smudge. For the delicate areas like the face and legs I use a 5-7 px, 0 hardness brush on 8-9%. For the rest of the body I bump the brush up to 9-15 px. This part takes a good amount of time. I do my best to smudge around any details that I want to keep. Doing this keeps the horse from looking like a smudged ball. After, I smart sharpen again around 30%.
Somewhere around this time I will try auto tone, contrast, and color on the horse and background layer individually to see if it helps unify them a bit. If that doesn't do enough I will mess with the brightness/contrast settings.
Highlights are next. I use a bright color taken from the background, then lightened/whitened a bit. I use the paint brush on 3 px, 100% hardness and paint on a layer with a clipping mask to the horse layer. I don't put highlights everywhere, just where the light would naturally be hitting the horse, or where I want to define more details (usually the cheek, legs, barrel, and chest).
I also use similar colors to draw in the eyes. I don't really have a go-to method for this, just whatever ends up looking good.
I smudge manes and tails. It's a goal of mine to get better at drawing them in. There's plenty of tutorials for this online but I can answer any questions if you really want to know how I do it.
There we go! Now the horse is prepped and ready for any final touches you're going to make.
Hopefully this helps!
Chilly and Clear with Dropping Temps
