Be Careful about the Apps You Install
An important step you can take to better protect your smartphone is to be extremely careful about what you are downloading and installing. The best rule of thumb is to only download apps from the Apple App store or the Google Play Store and not unofficial sites.
Apple does a great job of screening which apps become available through its App store. You can be confident that the applications you install on your iPad or iPhone are free of malware and viruses. The apps on the Google Play Store are more likely to have malware or viruses, but usually you can be confident when downloading from their store. Google has a scanner which scans its Play Store for malicious apps.
Also, it is important to check the permissions a new app is requesting when you download it. If a flashlight app is asking for permission to access your contacts, this should be a red flag.