[franzpeterfolz]

Don't start working on things you can't finish! Seriously. If tools are missing or requirements are not well defined or other people you depend on have not delivered now, than simply don't start.

This approach can reduce your work in progress tremendously. The benefit is, that it becomes easier to choose from your open tasks.

When everything you need for your work is ready, you can finish your tasks. Otherwise you start working and interrupt yourself because you have to wait for others.

Making assumptions on not not well defined requirements may lead you to work which will be discarded upon wrong assumptions.

And last but not least:

Work on things that matter.

Follow those things and I promise you that the disruptions will disapear.