I do my best drawing late at night, when there's nothing else I can be doing. My mind relaxes and lets itself get on.
Longevity of that state due to tiredness is an issue though.
I tried making one of my brain teas to help, but tried adding some guarana and camomile too. Nice flavoured blend, and a faster "boot up". Possibly because it is late, it didn't last as long and the wear off is somewhat rougher. I'll have to try it again tomorrow to see.

Still, got a good chunk of the commission tidied up and corrected. May well be able to do more in the morning.