Problem
Everything has to be labeled in a consistent location to make context or process completion clear...
Solution
Most pages should be labeled, including sub-tabs, sections, states. Pop-ups and other elements get titles, even sub-page elements, so mention that. Suggested is a straight up title bar, hence you see that in the diagrams here.
Variations
Except for very odd designs, always a horizontal bar or space with title in text.
Can include icons. Try not to be needlessly repetitive and use a more specific icon. For example, if a popup then don't repeat the app icon if the window behind is clearly the app. Either display nothing, or use the space for icons that indicate the state, such as an error triangle if there's an error.
Interaction Details
Generally none. Sometimes clicking a title does something, like jumps to home... Should this be a pattern or just a note it can do stuff... Anything it does should be related to the title bar, like jumping to top, not something random, and should be OS-wide if possible.
Presentation Details
Label everything similarly. Use the same voice, and tense, and capitalization, and so on. Basically, go hire a writer or at least pick up a style guide.
Antipatterns