1. Download non-android stuff
2. Download android stuff
First, Android SDK (let it add components after installation);
Then, ADT plug-in for eclipse.
3. Create a HelloWorld project
4. Run the project on a virtual device (aka. emulator).
[!] Make sure the Android versions match between the virtual device and the project.
5. Run the project on a real device.
[!] If you can’t find the device read here.