Also if possible please suggest me from where I can learn to write accurate subroutine for microstructure simulation because I am new on subroutine writing.
The application of Python and subroutine codes are often different in Abaqus. Here is an example of what pre-processing Python codes can do for you:
Conference Paper Utility of 2D Finite Element Simulations for Predicting Effe...
Also, here is a video summary of that work: https://youtu.be/0NLnCzW95fM
Please take a look at this and let me know if you had any questions. I think in either case, learning Python for Abaqus is a must, as it can make life so much easier! In the future, I will publish more research works that have taken advantage of Python pre-processing and post-processing codes.