Annoying when you click on a new tab to open and it opens on a blank page or a website you don't want it to open on and then you have to navigate to the one you really want..
There is a simple little add on extension you can install called "New Tab URL" and you can nominate what will open when you click on "new tab" in future. Download the add on from the above link and this will install it into Firefox.

After you download and it installs, close Firefox and open it again and to use the new tab add on, you need to click on "Tools" and "Add ons" to open the add on options box.

Click on extensions tab and you will see your newly installed NewTab URL extension. Click on the extension to highlight it and then click on the "Options" tab over on the right hand side of the highlighted extension and the rest is easy.. just configure it to open whatever website you want to open when you click on "New tab" in future.