HOW TO DO IT?

When we decide to realise realize(just a spelling mistake) a goal, we work on a plan which we think is the best to get the best results. But how can we planned plan for our goals? I think that life is a period of time, that's why, I think, we have to plan our work not according to things that we want to do (what we must do?).(full stop not needed, instead a comma would be best to create a pause) .but But according to the time we need to do it, and we ask ourselves : when we must do it?
So, I think, if we want to realise realize something, we mustn't determine what we'll do in a periode period of time, but how much time we have and we need to do this thing in (shouldn't it be-how much can we cover in this period?). For example: instead to  of say saying: I will read this book in a month.(comma instead of a full stop) , I would say : I will read this book in 100 hours (or more or less), and determine when it begins and it (not needed here) ends in time, (full stop for a pause) . so So, like this we could controle control the time that we spend doing this the thing, in ordre  order to controle control how many pages we read...