Installing the Eclipse and ADK

First download Eclipse
http://www.eclipse.org/downloads/

Start Eclipse, then select Help > Install New Software.

1. Click Add, in the top-right corner.
2. In the Add Repository dialog that appears, enter "ADT Plugin" for the Name and the following URL for the Location  :         https://dl-ssl.google.com/android/eclipse/
3. Click OK. 

If you have problem try "http" connection (  http://dl-ssl.google.com/android/eclipse/  ).

From time to time you should make updates.

1. Select Help > Check for Updates.
2. If there are updates available, select all, then click Next.
3. In the Update Details dialog, click Next.
4. Restart Eclipse.

After that .

1.  Select Windows > Android SDK Manager.
2.  Select all and install packages