How to solve problem

I have worked for 2 years in position it developer with different partner and I met a lot of problem in which also I found a lot of  solution.
One thing that I notice is the step to solve the problem as I will explain below.
1. we should know exactly what is the problem why it's became like that.
1.1 the method to find the problem is : unit test, compare code , find another example nearing our target if found apply that.
 2. thing of the solutions ( a lot of choice a lot of solution )  that we can solve easy and less coding.