i get that same feeling week in week out.
there's one thing that always sends me back into that state of total confidence and self-belief, on top of what goldheart suggested.
see yourself as some sort of divine being on earth. your every move graceful, your posture perfect, your smirk so cheesy it's a wonder why every woman isn't wanting to bite your lips off. whenever i do this, i feel like i've got an army behind me. and it's much easier to get yourself into this state if you have been working out, have been eating properly, have been drinking loads of water and have been getting a good deep sleep (8hours is spot on; try not to go over or under this. i don't know why, but i always feel like shyt if i sleep for more than 9hours.)
and one more for goldheart's list. quit jackin it for 5days at a time. a testosterone boost and more energy come from doing this, not to mention the mental gain, knowing you have the willpower to manage such a thing.
one last thing i've tried. whenever you do find yourself in that "zone", make some sort of distinctive movement with your arms, like twist certain fingers back or twist your arms out to the sides. this anchors the feeling you have in that zone and upon performing the distinctive movement again, you should be able to enter that same state. as crazy as this sounds, it doesn't hurt to try it.