Radiotherapy Field in Field technique

Hi everyone. I am a new medical physicist in my radiotherapy department. Currently i am facing difficulties in doing the field in field technique bcs i do believe i have not yet master the art of radiotherapy- putting the beams precisely, weighting points, optimizing RT planning, reduce the weightage.

I would like to ask opinions/suggestions/insights from anyone in the field, how do i improve my technique? What are the related references books that i can follow?

Thank you so much everyone.