Start by writing down the ideas you have. They don't have to be good. They just have to be written. The more you write down ideas, the better you will become at having ideas because once an idea is out of your head and down on paper there is no reason to keep turning it around in your mind and your mind can move on to another idea.
By writing out the idea that you are considering in your head, you can organize the inside of your head and look down on.
I think that Value Stream Map is good as a method to use for look down on, but how do everyone's put out ideas?
Good luck.