Accustom yourself to regularly check your phone bill and investigate any suspicious charges even if these are minor ones, understand app permissions before installing apps, use a trusted security app to protect you from malware and make sure to download and install critical updates. Malware that sends premium-rate SMS from your device will continue to dominate the 2013 mobile threat landscape and most devices lack the necessary protection mechanism against this type of malware.
Read more here – https://blog.lookout.com/blog/2012/12/13/2013-mobile-threat-predictions/