Please Help me compile a list of Effective Android Programming techniques

1. Don't forget to free resources after use.
   Lot of resources like Cursors are overlooked. Free them too.

2. Don't Use magic Numbers.
   values[0] is meaningless. The framework provides very useful accessors like values[SensorManager.DATA_X]

1. "Make use of onPause()/onResume to save or close what does not need to be opened the whole time."

   protected void onResume() {
   mSensorManager.registerListener(...);
   }
   protected void onStop() {
     mSensorManager.unregisterListener(...);
     super.onStop();
   }
   

2. Make your Android UI Fast and Efficient from the Google I/O has a lot of useful UI Performance tips.