Love the good
There's an idea in Christian theology that there are no real atheists. Everybody has her god or gods, those things that she worships, those for which she lives. Yours might not be the God who became a baby in Bethlehem, but so long as you live, and especially if you live with vigour or with anything resembling purpose, you have at least one, be it money, sex, power, respect, intimacy, novelty, familiarity, freedom, reason, your dreams, your partner, your family, or yourself.
The same logic is more often used on Christians as on non-Christians ("first take the log out of your own eye!"). You say you believe in God, and that there's no other god apart from him? Then why do you work so much? When was the last time you missed a major match by your favourite football team? Why would you lie, steal, or maybe even kill for your partner, even when (s)he's gravely in the wrong?
"Okay", an atheist (maybe you) might say. "I'll ignore your semantic sleight of hand and say, yes, I'm not an atheist by that definition. I kinda worship money, sex and power, but more than those I adore my partner and love myself enough that, on this silly line of thinking, they're my chief gods. What's wrong with that?"
Maybe quite a lot. And the key insight to seeing why is to note that, over time, you grow around and you are formed by what you love and what you worship.
Love money enough and you begin to treat (most if not all) people as solely means to that end. Get too attached to your public image and you hollow out your character. Worship freedom for its own sake, and you lose the kind of purpose that makes freedom valuable. Love your partner and yourself ultimately, and you distort everything else around you two, losing perspective of the truth and of the value of others as you instrumentalise them for your own ends.
But love the good – in money, in freedom, in others, in yourself, in the particular as well as the abstract – and you necessarily avoid instrumentalising that which should be valued for itself. Love the true and you won't long fall for distortions. Love the beautiful and you'll find yourself repeatedly surprised by joy. Don't just love the people and things and world around you, but love also the good, the true, and the beautiful in them. Be formed by them and not just by the things and people that you recognise them in. And if you're going to worship anything, if you're going to love anyone to the point of centring your life around them, love He who is the unity and source of all that is good, true, and beautiful.