Here are some things you can do to dramatically reduce the risk of malware infections on your Android phone:
1. Use the official Android Market instead of third-party app stores or websites, especially now that Bouncer is used to monitor for malware. If you want to help ensure that you only install apps from Android Market, you can turn off the ability to install apps from unknown sources in by going to Settings and then to the Security menu (in Android 4.0 or later) or the Applications menu (in earlier versions of Android).
2. Research apps before downloading: Check the publisher and app reviews.
3. Pay attention to app permissions during the installation and check the market listing or developer for an explanation of any suspicious permissions.
4. Install an antivirus/security app.
5. Be wary of phishing scams and malware via the web browser or SMS messages.
6. Be cautious if you root your device and keep an eye out for the Superuser prompts that are displayed when an app requests root permissions. Rooting allows you to use some powerful apps and even enhanced security functionality, but at the same time increases potential damage from infections.
7. To protect your Android device against local attacks - a thief or snooper - enable lock screen security (or, if you're one of the lucky few who already have Ice Cream Sandwich, you can test out the new Face Unlock feature.)
8. Finally, to prevent any malicious apps from sending messages to a number that will automatically charge your account, see if your wireless carrier can block the ability to sign up for premium SMS subscriptions.