How to develop patience in mathematics?

It's all part of the character building nature of the subject. But I find that it helps to have multiple questions on the go; once I can no longer stand one problem, I just put it aside, work on another problem, then return to it or yet another once I'm impatient with that one.

Take it in incremental steps: do five minutes more, then ten, twenty; an hour, two hours; an afternoon; a day, a week, a month, a year!

Note that some textbooks deliberately put in open problems as exercises.

Also, if you're planning on doing a research degree at all, you've got to learn which questions are fruitful and which to leave unanswered, bearing in mind that some questions can take decades to answer.

Always remember the Alexander_Grothendieck quotes "Mathematics is not a competition sport that who run fast they will win ( who run mentally fast)"

So you should never compare with other also that other are solving the problem easily

Most of the GRE-preparing students always compare with the other student GRE score It's is very bad and negative thinking because mathematics can not learned by overnight and rapidly

Terence Tao has said this

The objective in mathematics is not to obtain the highest ranking, the highest “score”, or the highest number of prizes and awards; instead, it is to increase understanding of mathematics (both for yourself, and for your colleagues and students), and to contribute to its development and applications. For these tasks, mathematics needs all the good people it can get.

Michael_Atiyah has said this

Advice to a YoungMathematician

''Be patient and persistent. When thinking about a problem, perhaps the most useful device you can employ is to bear the problem in mind all the time: it worked for Newton, and it has worked for many a mortal as well. Give yourself time, especially when attacking major problems; promise yourself that you will spend a certain amount of time on a big problem without expecting much, and after that take stock and decide what to do next. Give your approach a chance to work, but do not be so wrapped up in it that you miss other ways of attacking the problem. Be mentally agile: as Paul Erd˝os put it, keep your brain open''

You have to be practice patience, because by practice everything can be acheived . Practice make a man perfect

Reading solutions step by step might be a good habit to increase the patience. By that I mean, when you struggle with a question for $30$ minutes, if you have access to a solution to that problem, you don't have to read the whole solution. For example, first you can check the first idea and after understanding it, you can simply keep struggling through that idea for another $30$ minutes maybe. If you are still not able to solve it, you can go to a further step in the solution and take it from there for another $30$ minutes, not reading the whole solution.

However, there are few things to add here. There are some problems which are hard to understand but easy to solve. For those kind of problems, the solution might be a one line proof for instance so you may ask "how can I go through the solution step by step if the solution is too short?". In these kind of cases, I would suggest trying to have a better understanding on question. This could be achieved by reading more about the topic or turning back to the points where you could not grasp the intuition. Note that this kind of "struggling" also develop some kind of patience.

Finally, there might be some questions for which you don't have an access to solution. In this case, I suggest trying to find similar problems to the one you have. Sometimes, it is more satisfying (and even harder) to adapt an existed solution of another problem to your problem, than solving the problem itself.