Detecting malware is never good enough, by the time it's in anti-virus software it's out in the wild and has already infected countless systems (whether they're phones or computers). Some tips to stay safe:
1. Don't rely on Lookout to protect you. This doesn't mean uninstall it, but don't assume you're safe just because it's running.
2. Pay attention when an application is asking for permissions. Internet access and location are pretty standard for ads, but can a game send SMS messages? Can a wallpaper app make phone calls?
3. Why are you rooted? Do you need to be rooted? Do you need to be rooted all the time? If you don't need to be root, don't do it. If you do need to be root, pay very close attention to the apps that request it. A game should never do so, and only a handful of apps really have a good reason for it.