Chinese customers in an Apple store on Jan. 3, 2019, in Beijing, one day after Apple preannounced weak quarterly results that it attributed primarily to a sales slowdown in China. Lintao Zhang | Getty Images

When it comes to phones, the complaints I most often get from people are: "My battery life stinks!" and "Help! I'm running out of storage!" Apple has been working to fix both with changes to its software. It's easier than ever to see the clutter that's taking up all of the space on your phone, giving you more room for things you want to store, like music and new apps. Here are a few things you can do on your iPhone to free up some space.

Find out which apps you use the least and get rid of them

See which apps you don't even use. Todd Haselton | CNBC

Your iPhone might be loaded with apps you've downloaded over the years, but there might be a bunch hidden in folders you forgot about long ago. You can see which apps you use often and which ones you've never used. Just do this: Open "Settings."

Tap "General."

Select "iPhone Storage."

Move through the list and tap the apps that say "never used" and delete them. Tip: If you're removing a game that's really big and don't want to lose saves or other data associated with your account, you can choose "Offload app" instead of "Delete app" to save that data for later.

Keep your photos and videos in the cloud

Use Apple Photos. Todd Haselton | CNBC

One of the best ways to save space is to keep your pictures in the cloud. As cameras have improved on phones, the sizes of the images and video we capture have drastically increased. Google Photos is a lot of fun since it will auto-enhance them, automatically suggest albums and remind you of fun times in the past. You can download it from the App Store. Or, if you want to stick with an Apple product, check out Apple Photos, which has some of the features of Google Photos. Turn it on by doing this: Open "Settings."

Select "Photos."

Turn "iCloud Photos" on.

Check the option to "Optimize iPhone Storage."

Make sure you don't have the option to "Download and keep originals on."

Check the box to "Upload to My Photo Stream."

Let your iPhone manage storage for you

Let your iPhone manage storage for you by automatically removing apps you don't use. Todd Haselton | CNBC

Your iPhone is smart enough to manage software for you, and can automatically remove apps you don't use often to make room. I usually leave this option off because I want to know when an app is deleted first, but this is a smart way for your iPhone to manage its own storage. To turn it on: Open "Settings."

Tap iTunes and App Store

Turn the option to "Offload Unused Apps" on. See what your iPhone recommends you delete. Your iPhone will also make recommendations on ways you can save space. Mine says I can save 91.38GB by deleting all of the videos I've downloaded from iTunes, for example, though I prefer having those saved locally. To see what your iPhone recommends, do this: Open Settings.

Choose General.

Tap "iPhone Storage."

See what's listed under "Recommendations."

Delete music you don't listen to

Get rid of old Apple Music albums. Todd Haselton | CNBC

Spotify and Apple Music are relatively small apps, but they can balloon in size as you download music for offline listening. You should see if there are any songs you don't really need downloaded, since you can always just stream them over a Wi-Fi or cellular connection. To do this in Apple Music, do this: Open "Settings."

Choose "General."

Tap "iPhone Storage."

Tap "Music."

Swipe left on any artist to delete music you've downloaded, or swipe left on "all songs" and tap delete to start from new. In Spotify, you can save space by doing this: Open Spotify.

Tap the "Home" button on the bottom-left.

Choose "Storage."

Select "Delete Cache."

This will free up storage but won't delete all of your music. It saved me 1GB. Or you can delete saved songs by doing this: Open "Settings."

Tap "Playback."

Choose "Offline."

Now go to "Your Library" on the bottom-right.

Move through your albums and playlists with green icons showing they've been downloaded.

Tap an album you want to delete.

Toggle the "Downloaded" button to off.

Delete old videos you've from Netflix

Get rid of old movies in Netflix. Todd Haselton | CNBC

You might save videos offline for playing on a plane. They take up a lot of space, so you should get in the practice of deleting them. That will be one recommendation offered by your iPhone, but sometimes you might have downloaded them outside of iTunes, in apps like Netflix. To delete them, do this: Open Netflix.

Tap "Downloads" on the bottom.

Tap a movie or show you want to remove.

Tap the blue icon to the right of the show.

Select "Delete Download."

Clear out old iMessage clutter

Check how much space your messages are taking up. Todd Haselton | CNBC