Preflop: Always raises to about 5BB-7BB depending on the type of players there are on the table. And if someone reaised before you, make sure to reraise for these same values. If called all-in, you have to know which kind of players you are dealing with, if he played in a loosely style till now, you can call his all-in, but if he played tightly, he could be bluffing
cause he played tightly, or he could really be playing a strong hand, like QQ, JJ, or even in rare cases he will have AA or KK (since you've got AK, it's really unprobable he'll have one of these cards in hands, even harder to have a pocket pair of one of those cards.
Post-Flop: If you're not in an All-in situation, and the flop comes with and Ace and two other not significant cards, you can raise here to guarantee the pot if you think it's large enough for you, but if not, you can make a slowplay and hope the opponent doesn't hit another card. In case the flop comes with a King and any other face cards you can raise to take the pot too, but if some face card comes, like Q or J, you have to be careful cause the opp can have a hand like QQ, JJ, or even KQ or KJ.
On the turn and river just maintain the same thought, but always be aware if you think your opponent hits 2 pair or 3 of a kind, unless, play smartly and you will get a lot of chips from him.