Tip #1 - Check your mail(s) instantly (Windows 8)

Keep your Metro mail application open in background all the time. That way, you'll get toast notifications when you get a mail, and you can instantly check your mail with only one click in the top left corner.
To go back to what you have been doing previously, just click the top left corner again.

Eclipse pin to taskbar problem (Windows 7/8)

If you wanted to pin Eclipse IDE to your taskbar, and noticed that it creates another icon right next to the pinned one, you might wanna continue reading on how to fix that.

First, you need to find your Java Runtime Environment directory. It's usually
"C:\Program Files\Java\jre7\bin".

Copy the location, and open up "System properties" in Computer (Right click-> Properties when in Computer).

Now, go to Advanced System Settings, and click Environment Variables.
Select the "PATH" variable in the second list, and click Edit.
Move the cursor to the beginning of the textbox, and paste the location of the JRE.
Add a semicolon immediately after the location and press OK.
Close the remaining dialogs. 

If you have Eclipse pinned to the taskbar, unpin it first, run the .exe, and pin it afterwards.