I think there is a lot of wisdom in that old chestnut–that the best way to get really good at writing is to write a lot! And read a lot. Saturation reading, basically.
The Best Way to Get Really Good at Writing
And if one has neither time or energy to do either.
Then, trust God from whom all creativity flows!
Now that I have a lot less time, I just plunge into writing when free slots slow up. I remember however the days when I had lots of time, and slowly “got into the mood” by a slow process of arousal, by reading poetry, or reading prose until the rhythms built up inside me, started thudding in my veins, and I felt a burning longing to write something as beautiful as what I had just been writing