Let's pretend that you forgot how to reopen closed tab in Chrome. All you remember is: the menu item is called "reopen something".
1. Hit ⌘? (slow motion instant replay: Command-Question mark). This shortcut activates help search field.
2. Type "reopen" in search box. It's quite logical: the command we're looking for have something to do with reopening, thus searching for "reopen" is pretty reasonable.
3. Select "Reopen Closed Tab" in search results:
⌘? is a great way to find menu items by name. By the way, it works with every application.