Do you wait for "the right time" to write something or just start writing anything until an idea comes? (for writers)

I used to write randomly whatever came up in my mind. But nowadays I put in a message/moral to my stories and plan the best way to put in the message.
For you who hates self advertisement, Stop Reading Now!
I know some doesn't like self advertisement, and I'm sorry, but I feel an urge to do it anyway.
I'm currently writng a story with several versions on several See More places ^^ One on qfeast, one on my blog (iyagihada.blogspot.com), one in swedish and one on "OneNote". The first two is for everyone while the last two is only visible for me/on my ipad. The one on my blog focuses on the message while the one on qfeast focuses more about entertainment and bonus chapters. The story is: my future ghost (or: Je future ghost)

I usually find inspiration in people and nature, and feelings. I'm doing that right now, but cant think if anything. I just get a random idea or sentence, and try and add it my song that I'm working on. Either poems or songs I'm writing on.