Initial Setup
setup your environment

Let’s start from the very beginning of getting setup for Android development. These steps are mostly paraphrased from the Android developers website: http://developer.android.com/index.html

*The following instructions are for a computer running a 64-bit version of Windows 7, please install the appropiate package versions for your computer if you are using 32-bit Windows or if you're on a Mac

SDK = Software Development Kit
JDK = Java Development Kit
JRE = Java Runtime Environment
IDE = Integrated Development Environment
ADT = Android Developer Tools

1. Download the Android SDK from here: http://developer.android.com/sdk/index.html
Unzip this file to your desired location. I have mine extracted to C:\android-sdk-windows

2. Download the JDK from here: http://www.oracle.com/technetwork/java/javase/downloads/index.html
Click on "Download JDK". You will not need to download the JRE as it comes bundled in with the JDK. After downloading, follow the instructions to install.
*Unless you are experienced, I suggest not changing the default file path of the installation.

3. Download the Eclipse IDE from here: http://www.eclipse.org/downloads/packages/eclipse-ide-java-developers/heliossr2
Click on "Windows 64-bit" or your respective version on the right under Download Links
This is self-contained application, meaning you won't have to "install" it, it will run directly out of wherever you unzip it to. So, unzip it to your desired location.
For the purposes of this tutorial, the eclipse folder will be at C:\eclipse

Setup Eclipse

4. Go to your eclipse folder and run eclipse.exe
You will get the following prompt:

Click on Browse and make a new folder where you want your new workspace to be. This workspace will be where all your different Android projects will be stored.

5. If you see a welcome screen with several icons on it, find the workbench icon and click on it and you should see something similar to the following:

6. Installing ADT - ADT is basically a plugin for eclipse with tools that are needed for Android development.
Click on Help -> Install New Software

7. Insert the following in the "Work with:" field: https://dl-ssl.google.com/android/eclipse/

8. Check the Developer Tools checkbox to install everything available. Click Next several times and agree to the licenses until ADT is installed.
When the installation is finished, click Yes to restart eclipse.

9. After eclipse is finished restarting, click on Windows -> Preferences

10. Click on "Android" in the left column and then click Browse on the right and point to the location of the SDK we installed in step 1 and click ok.

Updating the SDK

11. Exit eclipse. The next steps can actually be done through eclipse, but sometimes not all updates are processed because eclipse is using some of the necessary folders.
Browse to where the SDK is installed. In that folder, run the "SDK Manager.exe"
Click on "Available Packages" in the left column and check the top checkbox to install everything. Click Install Selected and follow through with the installation.
This will insure you have everything you need to start android development

Congratulations, you are now setup for Android development!