Can you relate to an experience in your life when you really, really, desperately wanted something, only to find out that had you received it, you would have been very disappointed, or even harmed by receiving it? Well, that's a perfect example of the need for non-attachment. Contrary to many teachings, non-attachment, in the yoga teachings, does not mean you should stop desiring things. Obviously, your desire should not involve harming others or depriving them of anything. Your desires should always include unconditional love.
It's okay to desire good things that can benefit you and others around you. However, at the moment we feel a desire, it may, or may not be in our best interest. Trust the Infinite Source, that loves you unconditionally, to provide you with what will help you the most, even if it isn't exactly, or remotely close to what you desired. You'll find that when you practice non-attachment, you will either receive that which you desired, or you will receive something even better than you desired. But you must remain non-attached to the outcome.
DECLARE WHAT YOU WANT...BELIEVE IT..ACT AS IF IT WERE TRUE...RELEASE IT!