Start by making your iPhone lock sooner.
You can set your passcode to be required immediately after you lock it, or in as little as 30 seconds.
On your phone, head to Settings, then Touch ID & Passcode, and enter your passcode.
Here, head to Require Passcode, and choose from the options.
Another security hole is in the control center that can be accessed from the lock screen.
If you lose your phone, someone can prevent you from finding it by putting your device in airplane mode.
To prevent control center from being accessible, head to settings, then control center, And toggle the slider off for Access on Lock Screen.
And finally, if you haven't already, enable Find My iPhone.
With it enabled, you can track your lost device from another iOS device or your computer and see where your iPhone is on a map.
In San Francisco, I'm Sharon Profis.
CNet.com for CBS News.