If you're in Safari and you'd like to navigate to a different page without leaving your current one, what do you do? Why, you open a new tab or window and type in where you want to go, right? Well, there's another way to do it, and it's especially good to know this if you accidentally start typing into Safari's Smart Search field without opening a new tab first. After all, it'll save you from copying and pasting what you've already typed (or from retyping it, which is way worse).
All you've gotta do is type in a URL or a search term into that Smart Search field…
…then while you press Return, hold down the Command key. Depending on what you have set in your preferences (see below), this'll open your query into a new tab or window rather than replacing what's on the existing page!
Be aware, though, that this behavior is controlled by what you have set in Safari > Preferences > Tabs. If you've deselected ⌘-click opens a link in a new tab, then the Command-Return shortcut will open your query in a window instead. I guess that's not very surprising, huh?
Also, the preference in the middle of that window will come in handy—it's labeled When a new tab or window opens, make it active. If that's checked, then whenever you use that same Command-Return trick, the tab or window you're opening will get pushed to the front.
And finally, just for the heck of it, you might wanna check out all of the keyboard shortcuts that are listed in that Preferences window. Their behavior changes as you adjust your settings, and I think they're useful.
One more note: This tip will work in other browsers, too! In Chrome, the shortcut is the same; in Firefox, it's Option-Return instead, and it'll function in either the URL bar or the search bar. I dig that, man. I dig.