Or, what I should have said on the last day of my last class:

Never stop.  Philosophy is a discipline, and it is imperative that you keep it up, and deepen the discipline.  Otherwise, as the saying goes, your life, unexamined, will not be truly worth living.  Indeed, a life with no philosophy in it is only half-led.

Keep studying; and learn some logic, if you dare.  It's a hard master, and it will make you harder.  Keep reading - with a skeptical eye! - the best authors you can understand; and keep reading the impossible ones until you begin to understand them as well.

Above all, observe the world, and introspect - look within.

Your mind is the most amazing philosophical laboratory conceivable, with ready access to the most remarkable phenomena of Nature:  consciousness, perception and representation, decision and value, memory and identity, knowledge and opinion, virtue, and even wisdom.  This world inside you is a spectacle of amazing scope.  The fact that such things can be is one of the most profound problems of philosophy and a source of limitless wonder.

And keep an eye on the world outside you.  God or no God, Nature - including the human mind - is the principal self-revelation of the ultimate ground of being, whatever that may be.  If that ground is God, then Nature is the only scripture that all faiths recognize.  If not, then it is the only field on which universal truth expresses itself.  And among the sacred mysteries of nature, we find each other.  These, your fellow beings - what are they?  What do you owe them, and to which do you owe it?  Those who pay no attention here may become monsters while believing they are saints.

Never cut yourself any slack.  Question every belief you have, and force yourself to be answerable for the basis on which you believe - is it conventional, based on fear of belieiving what others would reject?  Do you hold a belief solely or mostly out of loyalty to your parents or your community?  Cast it away, or force it to account for itself on better grounds.  Search yourself for unraised questions, for hidden assumptions, for inconsistencies, for failures to live up to your own principles - and search yourself for principles that you have, but should not, or should have, but do not.

Never stop pushing yourself beyond what you are, toward what you could be.