Manifesting the ultimate self peace

I have always wanted to feel my total best but the issue was keeping that feeling consistent. I have prayed, read many book on self help, attended classes/ events/ therapy, etc. Yet nothing seemed to be enough really. For the moment one of these tactics would work but it has now become a temporary feeling and nothing long lasting.  

How can someone manifest the ultimate self peace? Meaning when we feel good , how do we keep this feeling going?? The need to be serene and happy is like everyone's goal really. To truly be at peace with oneself is a desire many people long to succeed in. I believe to have a consistent peaceful happy feeling like this we must always practice and desire positive methods that adhere to our need to relax...old and new. Keep the faith, keep looking for peace.