How to think outside the box in critical problems?

Critical problems or problems in general need to be perceived and resolved with a holistic view.
Think about all the aspects involved in the problem and try to consider alternative solutions related to these aspects.
When you consider all these aspects and anticipate further challenges, you may more likely find more solutions that are unusual and truly out of the box.

Out of box thinking does not come just like that.
For acheiving this quality you have start looking at every thing from different point of view.
Suppose you go to a garden then just analyze the foundation design and sequence and apply your mind to improve it even though it is not relevant to your professional or personal life.
But with such kind of thing you can develop the way to look at the thing differently.
In case if you some issue where you want some assistance then you can forward the problem with little brief, I will try to give some idea.

Generally the young people are better out-of-the-box thinkers, due to the lack of routine. So the best option is a team with youngsters to give their 'crazy' ideas (based on a solid academic background though) and seniors to estimate which of these ideas is worth further considering.

out box thinking, for me, means first to be aware of the typical " standard and common " solving methods, full awareness of your tools and the major element is not about inventing new methods and another gap of resources, but through full awareness of the available tools and their capabilities you can only find the outbox solution.
wrapping up the idea, mainly the out box thinking is about realizing the other capabilities or ur current tools and realizing the real roots of the problem.