I hope this doesn't come across as self promotion. I just wanted to share this single python script solution that I cooked up for myself.
https://github.com/kiriappeee/mynotetaker
It creates a markdown file that corresponds to the date you are making the note (so 2018-06-06.md) and adds a timestamp as a secondary header into the markdown file before opening the file in an editor of your choice.
I've gone over the top here and I have this directory linked to my Dropbox folder so everything is in sync. Whenever I need to jot something down I simply use `n` or `note` in the terminal, take down my notes and save it when done.