If you want to know how to become a better singer in just a few days then listen up! There is no magical way to do this, no controversial or little known technique! Singing takes practice and passion and dedication. However, assuming you have these things then there is one little trick that if you have not practiced before will help you sing better in just a few days but is certainly not the whole story.
This method is to help you sing more clearly and with better pronunciation. Not only does this make it easier to listen to but it will allow you to achieve clarity of voice and a precision of sound that will set you above other singers.
The way to do this is the sing the vowels in the alphabet. Try singing them without a tune for a while and then try putting it to music. If you make sure your vowels are crisp and well formed you will put your mouth and tongue in the right positions for better singing.