Can someone give me some tips as well as some links so that I can make my Android app more efficient and faster. Thank.
It really depends on your situation and how your application is built, there is no right or wrong answer, but this documentation can give you good recommendations http://developer.android.com/guide/practices/design/performance.html
For memory leaks, pay attention to traceview http://developer.android.com/guide/developing/debugging/debugging-tracing.html