I'm sure the well-studied have a word for "a philosophy that can yield an action plan" but I don't know it, so I'll make one up. I'll call that an actionable philosophy.
The problem of is-ought notes that many philosophies start by describing what is, and then warrantlessly transition into what ought to be done. I start from the question of what ought to be done and seek a connection to what is.
Firstly, I utterly reject nihilism as a practical source of actionable philosophy. By definition if nothing matters nothing needs to be done.
Secondly, I disregard every action that has not been reasonably proven to lead to a real result. I could invent a God of Hairy Asses and pray to him night and day, but like every other endeavor of faith it would probably prove fruitless. If you insist on believing in the supernatural, please depart the train of thought at this stop.
Thirdly, I reject actionable philosophies that would lead to pointless death. This introduces the bias that a human is intrinsically valuable. If you think you're no more important than a car tire or a pack of gum we have little to discuss.
Fourthy, I confine my philosophy to the human entity. A human has evolved to seek certain things. Things his ancestors did that let them reproduce. A human is 1300 grams of fatty computronium. Thus he is bound to real existence. A human is bound to a body, and thus the things it needs.
Fifthly, I define pleasure as the things a human tries to obtain if he is otherwise unconstrained and displeasure as the things he seeks to avoid.
And sixthly, I use the term "rational" with great consideration. A rational being has a goal and a worldview. She analyzes the worldview, and attempts to enact a decision that will bring a desired worldview in like with the existing worldview.
A useful philosophy must contain some drive: It must seek an end. (if you want to say the road is more important than the destination that's fine, but then I'll call the road itself the drive you're trying to aim at.)
If we fail to address the things we innately desire we must instead address things we don't desire. For each undesired thing we seek (and therefore seek to achieve), we give up a desired thing.
What, outside of human desire, is there worth seeking? Let's create an idea. I want to say freedom, or enlightenment, or Wisdom, or Beauty but these are all loaded and my intent is NOT to say any of these are undesirable. So I'll invent a word: Pafta. Let's say that every human is enriched by Pafta even if it's unpleasurable to have it. Then what you're seeing is the enrichment, and you have to follow a path to the reason this enrichment is more desirable than pleasure.
If you are utterly unbiased that path must end in a different form of pleasure. From wisdom, an ability to make the world a better place. From having a better world, pleasure. (and second-hand pleasure is pleasure too) From beauty, pleasure directly and second-hand, from knowing others can experience beauty. From art, beauty. Or from art, wisdom. Or from art, knowledge, which has its own path to pleasure. Pafta is defined by the pleasure it brings, and every ideal higher than pleasure returns to pleasure or avoiding displeasure.
So I claim that all high-minded ideals are complex ways to prescribe which pleasure a person ought to seek. So I say that any of these ideals, or any other still fails to escape the ultimate drive to pleasure. So I say creation and maintenance of pleasure is the highest ideal.
I could similarly address displeasure as the opposites of what is sought, but I think it's inherent in the above argument.
Therefore a rational decision ought to be a hedonistic one.
At first I had said "hedonistic utilitarianism" but utilitarianism is a separate argument I may make later.