How to improve as a rigger

So because my studies are finishing, I reflected a little bit on the past and here are my conclusions on how to improve / learn the most from a student perspective and optimize your demoreel. I personally did not think about some points and/or did not have a choice, so my past does not fit this description very well.
But of course you should always do what you enjoy most. And most of the following points happen automatically over time anyways.

1. Specialize in rigging. The more time you spend on other disciplines, the less time you will have spent on rigging. Note: Of course it is good to have a basic understanding of all connected areas, to improve working with the different co-workers (modelers, animators, r&d, pipeline) and to be more independent, require less feedback and be able to give better feedback. But after the basics there will be a moment, when it is better to do more rigging instead.
2. Work closely with animators as soon as possible. Because they are the people that use your rigs?! If you are an animator yourself, this is not as important. But there are also different preferences between animators.
3. Work with experienced/specialized co-workers. Because animators will know what they want and if they have a lot of experience with different rigs, they will request the nicest features they know and improve your rigs that way. Good modelers will ease/improve deformation. And generally the better the co-workers the better the end-result, which will make your work look better. And you can learn more from each other.
4. Work on few projects (quality>quantity) with people that work on few projects. If everyone has more time the quality of everyone's work should be better. Also the shorter the length of the film the better the quality (animation, rendering,..).
5. Create few character rigs (quality>quantity). Try to find projects with few characters (or do not rig all of them if there are too many). To improve quality and because you can only show a few rig demos in your demoreel. Note: It is also important to learn how to improve pipeline/workflow/speed. If you have to rig a lot of characters you are forced to do that, but you can still do it with a few characters if you want to.
6. Rig extreme (cartoony/realistic) characters. That way you learn how to create extreme motion (2D style) and recreate anatomy (deformation focus) in CG. If your character is stylized in-between you don't learn as much about anatomy, because it is not required (same for extreme motion). It basically is about having a good/clear target to aim for. Note: Some people probably want to focus on either cartoony or realism, so the other area can be dropped. That way the quality should improve in your area, but it will reduce the amount of companies you can apply to.
7. Rig different kinds of characters/creatures: Biped, quadruped, bird, snake, mechanical, ... Because they have different requirements and anatomy.
8. Scripting: Learn to script, to automate repetitive tasks. Optional: It can also be good to learn programming to: 1. Write better scripts, that other people can work with 2. to create new tools for other people to improve workflow 3. Write plug-ins for new functionality 4. Design a pipeline... These things are usually done by more experienced professionals. For a student it probably is better to keep it limited (see point 1.).

So if your main focus is improvement, you are starting to study and you have all choices, you would (after you have learned the basics of cg and specialized in a discipline): Only work on two projects/shorts for a long time (one realistic, one cartoony). Each time only rig a few characters (1-3) of different types (biped, quadruped,...) and everyone involved will have specialized in their discipline with a basic understanding of everything connected to their discipline and only work on a few projects as well.

My CG experience per subject

This graph shows the amount of time I spent on the different subjects and was made for my graduation presentation at Filmakademie. I found it interesting to give myself an overview of how much time I actually spent on each discipline. The measuring unit is "full time months" (20 days, 7 hours each). And it is normalized, so if I have done multiple disciplines at the same time I had to divide the time for each of them. My resume helped me to get a fairly accurate estimation.
But of course my prior programming knowledge (B.Sc.) helped learning scripting and the Maya API faster. And most scripting was done for rigging, so they are connected quite heavily.

I guess recruiters try to extract this information from resumes, but I think it can be difficult. For example listing disciplines / software / programming language, with the number of years they have been used, is not really useful because it does not actually describe the amount of time and the context (hobby, study, job). Except if it can be matched with job descriptions etc...
Also it may be interesting to know how much time someone spent to get to the work done (productivity / efficiency?) in the demoreel and the time spend to achieve the skill level (talent?). To predict costs and growth of the employer?

Maybe I have recently looked at too many company job pages and other peoples resumes, since I am looking for my first real job after graduation. But I don't understand why students rate their own skills with "expert", "intermediate", "beginner". I personally just keep it neutral in my resume/linkedin with these lines:
Specialities

Primary: Rigging, Scripting

Secondary: R&D, Modeling, Cloth Simulation