Android Development Tools: Which Packages to Install

As a minimum when setting up the Android SDK, you should download the latest tools and Android platform:

1. Open the Tools directory and select:
   • Android SDK Tools
   • Android SDK Platform-tools
   • Android SDK Build-tools (highest version)
2. Open the first Android X.X folder (the latest version) and select:
   • SDK Platform
   • A system image for the emulator, such as
     ARM EABI v7a System Image

The Android Support Library provides an extended set of APIs that are compatible with most versions of Android.
Open the Extras directory and select:

• Android Support Repository
• Android Support Library

To develop with Google APIs, you need the Google Play services package:
Open the Extras directory and select:

• Google Repository
• Google Play services

Note: Google Play services APIs are not available on all Android-powered devices, but are available on all devices with Google Play Store. To use these APIs in the Android emulator, you must also install the the Google APIs system image from the latest Android X.X directory in the SDK Manager.

Source: http://developer.android.com/sdk/installing/adding-packages.html