About the time my iTunes music library reached 5,000 tracks I knew it was time for a cleanup. While I was at it, I adjusted the volume on some tracks that I had converted from audio cassettes, made sure joined tracks play in sequence, set iTunes to fill my iPod automatically, and learned some handy playback-control keyboard shortcuts.

Now I'm spending more time listening to the tracks in my iTunes library and less time skipping, scrolling, and searching.

The semi-automatic way to remove duplicate media files

iTunes provides two options for identifying duplicate files: one based on the song name and artist, and another "exact" method based on the song name, artist, and album. To see a list of files with the same name and artist, choose the library in the left pane and click File > Display Duplicates. Press the Shift key in Windows or the Alt or Option key on a Mac and then click File > Display Exact Duplicates to view files with the same name, artist, and album.

To ensure you're deleting the lowest-quality duplicate, show the Bit Rate column in the file list: click View > View Options, check Bit Rate in the Show Columns list, click OK, and then drag the Bit Rate column to the left so it's visible next to the song name, artist, and album.

Screenshot by Dennis O'Reilly/CNET

If you want to delete the older of the duplicates, sort by the Date Added column (if the column isn't visible, click View > View Options, check Date Added, and click OK). If you're an iCloud subscriber, click the iCloud Status column to list all the duplicate files together.

Select the duplicates you want to remove by Ctrl-clicking, Command-clicking, or Shift-clicking them, as the case may be. Then press Delete. You're then told the files will be removed from you media player on the next sync, and you're given the option to keep the files in your iTunes Media library or placing them in the Recycle Bin or Trash. (iCloud subscribers are given the option to delete the file from their iCloud library.)

Screenshot by Dennis O'Reilly/CNET

Depending on your media collection, you may have duplicates remaining after you delete the files iTunes identified as duplicates. It took another pass through my library to find the few dozen duplicates that iTunes failed to spot. Still, the semi-automatic dupe-deletion method shrank my library by more than 15 percent.

Link tracks to play in sequence

I'm a fan of shuffling the songs I listen to from my library, until the third movement of Beethoven's Sixth Symphony plays without being preceded by movements one and two and followed by movements four and five. (If I had followed the steps below to join CD tracks when I ripped the disc, I wouldn't need to connect the tracks after the fact.)

You can tie together separate tracks of a single piece of music or the cuts from one side of an LP (think Pink Floyd's "Dark Side of the Moon") if the track numbers are sequential, and the tracks have the same album name.

There are two ways to ensure separate album cuts play in sequence: right-click each track separately and choose Get Info > Options > Part of a gapless album > OK; or select all the tracks at once, right-click the selection, choose Get Info > Yes (at the warning about editing information about multiple files at once) > Options, choose Yes in the drop-down menu next to "Gapless album," and click OK.

Screenshot by Dennis O'Reilly/CNET

As the Apple support site indicates, gapless playback is on by default in many iPods and iPhones, unless their audio-crossfade feature is enabled (crossfade is off by default). Unless you're listening on shuffle, most contiguous tracks will play as intended without having to enable gaplessness.

Join CD tracks when you rip them

There's a simple way to avoid having to link tracks so they play in the appropriate sequence: tell iTunes to join the cuts before you rip them from the CD.

When you insert the CD, iTunes will ask whether you would like to import the tracks. Click No, and then select the connected tracks by Shift-clicking (note that iTunes can join tracks only if they are listed together). Once the tracks are highlighted, click Advanced > Join CD tracks. A small black line to the left of the tracks indicates that they are linked.

Screenshot by Dennis O'Reilly/CNET

After the tracks are joined, click Import CD. Once the import is completed, the connected tracks appear in your library as a single entry.

As the Apple support site indicates, the Join CD tracks option requires that the tracks are selected on an audio CD, that the tracks are contiguous, and that the CD is sorted by track number in ascending order.

Now playing: Watch this: Make iTunes sound better

Use the Sound Check/Equalizer to adjust the volume of single tracks

In July 2011 I explained how to use the free Audacity audio software to convert LPs and audiocassettes into MP3s and CDs. Hundreds of the songs in my iTunes library were transferred from a tape or vinyl record. Unfortunately, the volume of these tracks is often much lower than the volume of original MP3s and tracks ripped from audio CDs.

iTunes lets you adjust the volume of individual tracks via the song's Options dialog box. Select the track, right-click it, and choose Get Info > Options. Move the volume-adjustment slider to the left to lower the track's volume or to the right to increase its volume.

Screenshot by Dennis O'Reilly/CNET

You can also choose one of the equalizer presets from the drop-down menu below the volume adjuster. The presets include spoken word, bass booster, acoustic, jazz, vocal booster, and small speakers. Click Next to open the Options dialog for the next item in your library. To adjust a track's equalizer settings manually, click View > Show Equalizer (Windows) or Window > Equalizer (Mac).

Let iTunes fill your media player when you sync

If your iTunes media library fits on your iPod, iPhone, or iPad, you can let iTunes sync the items in the device automatically when you connect it to your computer. For those of us whose library exceeds their media player's storage capacity, iTunes has an option that automatically fills the device with selections from your library.

Connect your media player and choose "Manually manage music and videos" under Options. Then click the arrow on the left side of your device entry in the left pane and choose Music (or whichever type of file you want to fill the player with). Click the Autofill button in the bottom-right corner of the track-list window to have iTunes add tracks from your library to the device's capacity.

Screenshot by Dennis O'Reilly/CNET

Use the Autofill From drop-down menu in the bottom-left corner of the main window to select the library from which tracks will be pulled, and click the Settings button on the right to reserve space on the device. The option to choose items randomly is checked by default; the other two settings let you fill with higher bit-rate tracks first, and replace all items when autofilling.

Save time with iTunes' playback-control shortcuts

To switch to iTunes' mini-player in Windows, click View > Switch to Mini Player, or press Ctrl-Shift-M (press Ctrl-Shift-M again to revert to the full iTunes window). On a Mac, click Window > Switch to Mini Player, or press Command-Shift-M. But you can control iTunes' playback without any player visible by using keyboard shortcuts.

The shortcuts corresponding to each iTunes option are shown on the main menus, which you can open in Windows by pressing Alt and then the underlined letter that appears in the menu item. On a Mac, press Control-Fn-F2 and use the arrow keys to move between and open the menus.

The Apple support site provides lists of iTunes 10 keyboard shortcuts for Windows and shortcuts for the Mac, as well as a compendium of Mac iTunes keyboard shortcuts.

I know: Who's going to remember another four or five dozen keyboard shortcuts? The shortcuts that I find most useful are for controlling playback (they also happen to be the easiest for me to keep in mind):