As much as it may seem handy to keep many windows open in your screen, ready to work with, they are more likely to become a focus trap. Instead, have a super easy super quick way to open whatever you want in a blink and keep fewer windows and tabs open.
>>>

Interruptions' costs, "completeness-thirst" and protective contexts.
>>>

Use at least a part of your day to Deep-Focus activites. Allow yourself to disconnect from everything(!) for a period of time and dive into some high-value complex tasks.
>>>

If you want to optimize your focus at any moment, take a piece of paper and write down what you're thinking of - specially, what are you worriyng about?
>>>

How does brain handle focus? What happens when we multitask? Is it productive?
>>>

Work in time slots of high focus. Bundle small things on a list to avoid focus-shift. Like traffic lights, things get better if they have a kind of rhythm.
>>>