You can also drag items to the iTunes LCD (the display at the top of the window). If you press the Option key and hover over an item, its track number will change to a plus (+) icon; click that to add it to Up Next. (Alternatively, you can press Option-Enter to add selected items, but this will add the items only to the top of the queue, not to the end.) Click the Up Next icon to open a popup window containing a list of whats to be played; you can reorder your play queue from this list, or delete songs that you no longer want to hear. Apples updated Remote iOS app integrates with Up Next.
Up Next employs a new kind of contextual menu. When you hover your cursor over a song, a small arrow icon appears after its name. Click this, and you'll see a contextual menu containing a number of commands, including those for Up Next, as well as others for adding songs to playlists, starting Genius, viewing items in the iTunes Store, and more.
Although Up Next is a very useful feature, initially it's confusing. You can add items to the queue in various ways, but those ways are inconsistent, and it takes time to understand exactly what happens when you have songs in the queue and add others. Also, a perplexing dialog box appears when you have something in the Up Next queue but you go to play something else. The program asks whether you want to clear the songs in the queue -- an odd question, since iTunes doesn't offer to put the songs at the end of the queue.
The MiniPlayer has been redesigned as well, and now functions more as a control center for iTunes. In addition to providing the standard controls for play/pause, next, and previous, it shows you whats queued up in the Up Next list; also, a search field lets you find songs, albums, and playlists, and either add them to the Up Next list or play them immediately. Searching was abysmally slow in my 65,000-track library: I sat through more than 20 seconds of a spinning beachball before getting results, though those results were useful and practical. (On my blog, I posted a video of just how bad it was.) I found the MiniPlayer so useful that Ive set up iTunes to display it all the time. (Since I use Spaces, setting up MiniPlayer for permanent display wasnt easy; this hint explains how to do it.) In a perfect world, I would frequently use this search field to find what I listen to from the MiniPlayer window, and to avoid visiting the main iTunes window as often.