I prefer segment rather than single rating. I train on problems rated from x to x+500 where x is my rating.

1. Solve problems with a bit higher rating. If you encounter harder problem then think about it for some time, make sure you are learning from the problems.
2. You cannot solve any problem quickly. It's impossible. There are always problems which are easy for you and you are able to solve them immediately and problem which are hard for you and you need much time to solve them. Only way to solve problems quicker is to move up this boundary which separates easy problems from hard ones.
3. Codeforces is good place but you maybe want to try some other CP websites like AtCoder or CodeChef.

It means solving a problem which you weren't able to solve earlier (for example on contest).

Everyday I take some time to think about harder problems and upsolve them (most often in the evening). I solve new problems only when I want to.

I will add something. When you are reading editorial then not only try to understand the solution but also ask yourself how you can come up with this solution on your own.

If somebody has a higher rank than you then you are in no positon to teach that person how to learn because this person probably knows more about learning. I agree in fact that thinking is more important than knowledge but you must also notice that higher ranks need some more advanced knowledge than binary search.

To be honest you are the only person who can know what you can improve. Reason for that is because there are many things which could be going wrong. Maybe you cant solve harder problems because you don't know how to think? Maybe you cant solve harder problems because you don't know needed math? Maybe you know how to solve harder problems but you stress out too much on contest? Maybe you have troubles with writing code or maybe troubles with debugging? The issue is that there are many thing which could be going wrong so nobody can give you the best advice.

Observe what are you doing wrong and try to see some patterns in that. After you see these error patterns then try to come up with how you can overcome this weaknesses. The answer may be for example to change how you practice, how you think or change your attitude. And of course, the most important thing, have fun.

I think they are more effecient in their learning from their mistakes and they are more engaged.

I started observing what errors I make in thinking (like being stuck in one approach to a problem or over-complicating stuff) and began using that knowledge to improve my thinking processes. Also, when solving a problem, I began to ask myself, "What do I know and what this implies?".