...to explain how to form a good idea. (Para. 1)
form a good idea: begin to have an idea and develop it
We can say "to form an idea, an opinion, a judgment, a plan or even a personality".
He found it hard to form an original opinion. 他覺得要有獨到的見解并非易事。
I know them both well enough to form my own judgment. 我對他們都非常了解,足可以自己獨立判斷。
A plan began to form in his mind. 一個計劃開始在他腦子里形成。
One of the most important tasks for a school is to help and promote forming a child's personality. 學校的一個重要任務就是要幫助和促進兒童個性的形成。
vt. 促進,提升,升遷; 發起; 促銷