Another little gem I’ve been using for a while: org-toggle-narrow-to-subtree. I added an explanation to my emacs config:

Macro I created to focus on projects (headers in org-mode) that gets everything else out of the way. The idea is simple: when standing on a sub-header (in my case, this is usually level three. For example, I’m standing on “pay electric bill” in: * Personal > ** ACTIVE pay bills > ***TODO pay electric bill), jump to its parent (in this example, “pay bills”) and narrow. When running again, expand it back. This is working by using org-toggle-narrow-to-subtree. Very useful when working in a buffer with several projects.

(fset 'jr-project-focus
   (kmacro-lambda-form [?\C-c ?\C-u ?\C-c ?n] 0 "%d"))