What are the fundamentals of human figure drawing? How to improve in each of them?

A ‘gesture’ drawing should be an extremely quick sketch that you make just to place the basics of the form on your page. They are almost always LESS than 1 minute long, both the poses and the drawings based on them. It’s important not to look at your page when you draw these except perhaps for a starting position. It’s very important to look AT your model as you draw.
The purpose of these is actually to teach the artist to SEE the model – do not think of the exercise as making a drawing. Plan to throw out your gesture drawings.
If you simply LOOK at figures as you draw quick gestures, (make lots and lots of them), you will be well on your way to solving problems 2 and 5, since gesture drawing is designed as a process which will ‘teach’ to find form (2) and the basics of anatomy (5) as you do them.
Finding forms and the basics of anatomy in the context of successful gesture drawings means to place the head correctly, get the angles of the spine, shoulders and hips and show which leg the figure’s weight is on. You will probably naturally indicate the important joints such as knees as part of this process. If you find yourself with a few extra seconds to spare, try to hang the pelvis off that hip line, or the rib cage off the spine.
Do not look at any of your gesture drawings until after the ‘drawing’ session is over. Just do one, then another and another.
One final word of advice – you do not need a nude model or an art class setting for a session of gesture drawing. Indeed, un-posed unaware ‘models’ are ideal for this. People waiting for a bus, in line at a bank or movie and so on present a perfect opportunity to practise gesture drawing. Some will be looking down at cell phones or books, some will stare off into space, some will lean against walls, some will stand quite heavily on both feet, most will have one leg bearing the primary weight. Draw them all.

Perspective and values (by which I assume you mean light and shade) can be dealt with at later stages in your development. Most people learn them intuitively as they try to match what they see in their models or scene to what they are representing on their page. But first, try to learn to SEE, and any technique that has you drawing without looking at your work as you do it, such as a gesture drawing will teach you to see.