Most game theories are based on pot odds. When the pot odds tell you to call, raise, or fold, then you do it. Play solid cards to increase the odds of success, and bluffing at critical moments enough to keep your opponents guessing. If you can do that then you can probably beat limit hold 'em and stud in your sleep because your decisions become automatic. Unfortunately, no-limit is an entirely different animal because no decision is automatic and nothing is ever cut and dry.
What is the fundamental theorem of no-limit play? Well, apologies to David Sklansky but we need a theorem that applies to full cash games as well as heads-up play and we need it to apply specifically to no-limit play. So here is that theorem:
Between equally skilled opponents, profit derives from the mistakes your opponents make solely because of financial pressure. Losses are the result of the mistakes you make solely because of financial pressure.
This idea applies without exception to no-limit play. When you or your opponent make a call because the amount of money involved is insignificant or fold because the amount is too high for you to be comfortable then someone has made a profit. Whenever you act because of financial concerns you lose and someone else wins. It doesn't matter if the amount of money truly is important to you or trivial, it is absolutely imperative that you think and act as though it isn't. You must put the financial concerns into context as just one factor of many of making the correct decision. Winning in this game is about making the correct decision regardless of financial concerns.
If your opponent has no fear of the financial stakes involved in the game and is equally skilled as you then he cannot be pressured and only luck determines who will win a given session.