Here's a series of tips for learning anatomy!
From questions that have been asked to me in the past.
One of the questions that I've seen been asked multiple times is: How do I draw the same character using different angles, without messing up?
Well, there's a really easy method, which is basically using a circle. If you have already painted the character once, you may sketch on a new layer a circle, and a few lines which remark the position of the eyes, nose, mouth, ears, and very importantly: the jaw. On the following picture you can see the process of turning my Oc (in a furry style) around. From 3/4 to Front view or Profile view, as long as the lines obey the rule settled for the character, it will help making it look similar. Now, watch the lines carefully! See that the vertical lines meet under the circle? That's because the jaw is not inside the circle, but outside.
Human bodies have several differences, but there's a few basic rules that help the understanding of basic anatomy.
First, we shall divide between adults and children.
Adults are usually between 7 to 9 values of their head.
To easily find out where the joints are, one can cage the figure and the segments will guide.
For example, the elbows are located at the line between the 3rd and 4th segment, and the knees are usually situated at the start of the 7th. The wrists are at the same level as the genitalia area, on the 5th segment.
Children vary from 4 to 6 head value segments, as for 4 to 10 year olds. Again, difficult to say the exact sizes due to the difference in their growth.
The elbows are located at the end of the 2nd segment, and just in the middle of the 3rd there's the waist. The knees are situated at 1/4 of the 5th segment.
For babies and toddlers, they usually have a head value amount of 3 to 4.
For teenagers, it's about 6 to 8 segments.
Elderly people usually shrink a bit, but it still values as the adult body.
Painting a portrait is no easy challenge. Again, every face is differently formed, and a tutorial on it would be endless. But, here's a few general ideas.
The mouth is alligned to the interior side of the iris, usually. The nose alligns with the start of the lacrimal glands. Despite the "perfect" rule, the eyes are not always located within the distance of an eye.
For profile views, I have seen several times the nose being sketched with the nostril out of the main face area, on the curve of the nose. This is the wrong place: The curve itself is part of the nostril. So you can try to guide the curve in a soft wave before it reaches the tip of the nose. Again, every nose is different.
The ears are located right as the jaw ends. They are usually alligned to the mouth and to the eyes. Some facial expressions will move them slightly upwards!
Symmetry is bad! But not when you're learning.
When you are experienced enough, then you can rely in less rules and more freedom. This can portray more natural expressions. But when learning, you may need to use the tools that are given to you. Mirror guides can save you from a bad time. Difficulty on drawing eyes? Not the only one. Go ahead and copy-paste it to the other half of the face. You are learning, don't be afraid. But, after doing a copy paste, you may see something wrong with the iris and pupils looking different ways. Once you start correcting these details, you're showing the improvement. And when you're ready, you'll feel like the guides are not always useful anymore!