All you have to do is to click on "Get Free fuel". Unfortunately, FarmVille management has become very miser this time and instead of getting fuel tanks, you will get only one fifth (1/5) of a tank, only if other friends do not take everything before you even wake up.
You will be able to find the 1/5 Fuel Tank inside your FarmVille Gift Box.
For other ways of getting Free Fuel at FarmVille, you can click here:-
How to send Free Fuel to your Friends at FarmVille in different ways?