Does positive thinking works? I believe it does but, it requires actions and sometimes planning.
Positive thinking is similar to prayers or wishes, it is facing risks but, deciding to try it.
If you want something material or even emotional, you can not expect to simply sit around and wait for magic to happen. You must work for it, chase it, dedicate and persist. The reason I say positive thinking does work, it is because mental attitude is important on any decision, the desire to do it must come first, and this is the wishful thinking behind every success we achieve, rather material, emotional or physical.
It is that initial ignition to give us enough energy and focus to get things done.
Positive thinking helps maintain the focus on your goals, it is a mental exercise used to motivate the work, the efforts, the planning.
One just needs to become aware of this process and not become cynical, lying to oneself that just the mentality is enough.
Meditation or positive affirmations can work really well when you assess what are the things you could be doing to achieve your desired goal. If your problem is procrastination, becoming aware of this flaw and reinforcing the necessity to put the planning into action through meditation or positive affirmations is the only way to achieve it. And same can be said for many other flaws and mistakes:
Meditation or affirmations
That is the proven process.