Balancing between finishing past projects and working on current ones Personally, I never feel done with projects, as there are always a few open projects, in which I'm involved in. (And typically 1-2 which "I should have finished year ago or so".)

First, what are good strategies of balancing between finishing past project and working on current ones?

On the one hand, concentrating only on current ones means that there will be a lot of "almost baked" project, in a form of partial results, never published drafts or papers stuck in the revision process. (Assigning second priority to something means that it is never going to be taken seriously.)

On the other hand, focusing only past projects would:


look as if I were slacking off (also, as some past projects are from previous afflictions),
have me stuck in working on projects, which are going to be "90%" for the eternity.


Second, being put in situation with constant (internal) pressure and no calm sense of finishing things (as even after polishing results, polishing a draft, going through a few rounds of revisions... there are still n-1 open projects), is there a way to feel accomplishment and not blame oneself when resting?
This is a very broad questions, so I’ll try to chirp in with some of the “tricks” I use to get things done.

Find ways to keep track. It can be very easy to feel that you have so many things going that you feel overwhelmed by remembering them or else. There are a number of hardware or software tools to do that. I have a list of ongoing stuff that I keep in the last pages of my notebook, which works pretty well.

If something needs to be done, which takes little time, just do it right now. More importantly, the critical amount of time depends on the life of the project: the more advanced the project is, the more you need to finish. This prioritizes finishing older projects.
For example, if I have a current project with a task that requires half a day of work, I'll try to find a time to do it later. If I have a one day task for a project that's almost done (such as revising a manuscript after reviewer comments), I'll just treat it as high priority to do ASAP.

When working on a project with others, be clear to assign someone to monitoring progress (and reminding everyone of their contributions). On some projects, you need to take the back seat, and just let someone more concerned about the outcome drive the project.

If some project isn't seeing any progress, try to break it up into smaller work units. Like: I'll write a detailed outline, then circulate it to colleagues or co-authors, then use feedback to write the paper (instead of trying to write the paper in one big piece).


Finally, some advice I have received as a young parent, and that is very applicable to academic life: academic life is a long-term game, you're in it for 40+ years. You being very productive right now, then extenuated for 6 months isn't a net positive. You are a better researcher when you are rested and (relatively) stress-free, so avoiding exhaustion and stress is actually your #1 priority!