Ask HN: How to break up and delegate programming tasks

I can solve development problems in my head and transfer them to code without a problem. I can design the build the whole system and pass on implemention tasks to the other senior people. However I can not seem to break the tasks up ahead of time on paper in a way that a junior or mid level developer can use to execute the tasks. Does anyone have any resources or tips that I can look into to help me be a better senior developer to the not so senior devs?