The phenomenal improvement in the capabilities of modern smartphones, and the underlying `App' store model of software distribution, has fundamentally changed the mobile computing landscape. For many people, smartphones are the platform of choice for their computing needs. These trends have led to several interesting research problems that need to be addressed. Two of the major ones that we have looked at are energy management (or improve battery lifetime) and mobile privacy. To improve the battery lifetime of these devices, we have looked at optimizing communication energy consumption since it is one of the dominant components given the many radios these devices have (Bluetooth, WiFi, NFC, GPS, Celluar). Recently, our focus has been more towards 3rd party Apps running on modern smartphone OSes which can cause un-necessary battery drain due to developer error. We have built a tool that verifies Android apps for the absence of energy sapping bugs. The other aspect of mobile computing that we are very interested in is privacy, specifically for smartphone applications that collect and often sell user data such as location, contacts, various identifiers and other private data unknown to users. Our ongoing project - ProtectMyPrivacy - explores the extent of these privacy leaks, and provides users the ability to manage access to their private data. To help users make informed privacy choices we have implemented a crowd-sourced recommendation engine. There are multiple research avenues that PmP has opened up, for example understanding user perception and bias towards privacy on smartphones, effectiveness of crowd-sourcing, improving effectiveness of privacy prompts, and also understanding the motivations behind privacy breaching apps.