I use a self hosted kanboard instance for my tasks or todos. I use zim as knowledge base and journal. I bookmark stuff in a self hosted shaarli instance, and tag things I need to read later with the #read tag. In Firefox a bookmark link takes me immediately to my reading list.

In Fastmail, I make extensives use of labels to be as close as possible to inbox zero. Every email gets a label and gets sorted asap.

This is the results of years of experimentations but this is the longest I've been sticking to a workflow/tools.