Everything I know about painting, I learned in Mrs. V's art class. To be fair, I don't know that she really ever meant to be an art teacher. And I know she wasn't paid nearly enough. Still, I'm not sure foam tiles for the dropped ceiling trying to hide the asbestos covered pipes was the best art project for small children.
I try not to judge.
Step 1: The Dinosaur Sketch
Sketch out the loose form of your dinosaur. This is done in photoshop with a Huion 610Pro tabler. Huion can be had at a more affordable price compared to Wacom. Wacom is still the king among tablets though. Work with what you've got.
Step 2: Base Colours
Make a new layer if you're using photoshop. Here it only depends on what you want your final colour to be. I think my dino should be a light shade, so I'm laying down a yellowish-beige and some ruddy reds.
Step 3: Base Background
Throw down some purple on the canvas in a new layer. This will be a snowy scene, so I'm keeping with cool colours. You can try out different selections to compliment your dinosaur painting.
Step 4: Duplicate and Highlight
It's faster sometimes to duplicate layers you've already layed down, and then erase, blend, and paint as you need to. For the little cretaceous mammals, I've put down an icy blue, and then a light gray on top. I almost never use true white for highlights. For the dinosaur, I've blended the same light blue-gray for highlights.
Step 5: Eyes & teeth
Painting dinosaur eyes and teeth is a loose affair when I'm in a hurry. This Tyrannosaurid would also look brilliant with blue eyes. But we stuck with orange.
Step 6: Shadows
Since the light source is coming from above, the dinosaur shadows will be below. Use a new layer set to multiply and brush on more purple.
Step 7: Details
Here's where photoshop brushes will make your life easier. Feathers don't usually happen randomly, even on dinosaurs. They lay in rows. If you're new to painting feathers, I highly recommend "Owls" by Scholz, it's brilliant, and "Drawing Birds" by Laws. Both are excellent.
Painting scales deserves it's own books and tutorials as well. I often set that layer to "Emboss" and alter the highlight to match the light direction of the dinosaur.
Step 8: Duplicate Layers & Let It Snow
How to paint a snowy dinosaur? That's how! Hope you had fun.