eye up
1. To look at someone carefully in order to make a judgment about him or her. I saw the other poker players eyeing me up, trying to figure out if I was any good.
2. To look at someone or something in a way that indicates desire, attraction, or sexual interest. You're totally eyeing up that cute blonde over there, aren't you? I've been eyeing up the dessert menu, but everything looks so good. I can't decide what to order.