I literally write "// TODO: YOU ARE HERE - (Summary of next tiny task)" I separately keep a TODO file with the list of next major task items, and I break them

I literally write "// TODO: YOU ARE HERE - (Summary of next tiny task)" I separately keep a TODO file with the list of next major task items, and I break them down into subtasks if necessary. This allowed me to do a side project in 15-minute chunks on my train ride to and from work for a year