In general, players' slow play (meaning that you play your hand passively in an attempt to trap your opponent) much more than they should. The best way to win big pots with Aces and Kings is to play them aggressively pre-flop. When there has been a raise before you, re-raise (also known as a 3-bet) every single time. There are several positive outcomes when you do this. First, you give yourself an opportunity to put a cooler on your opponent when he also has a big (but not as big) hand. Let's imagine you have Aces and your opponent has Queens. If you 3-bet he is likely to raise once again and all the chips will end up in the middle, with your Aces having an 80% chance to win the huge pot. If instead you just call pre-flop then you have a chance of winning a big pot – especially on low flops such as 2-2-5 rainbow – but there are plenty of flops that can kill your action too. If the flop has a King or Ace on it then your opponent is bound to slow down, and the same would be true on a very co-ordinated flop such as 7-8-9 of the same suit. There should be nothing more frustrating to a winning poker player than realising they missed out on an easy opportunity to win a big pot.
There are few circumstances where slow playing will be more effective. One example however, is if you are up against a player who is very aggressive; in this spot you could just call a 3-bet with your big pair instead of re-raising because you sense there is a good chance he is bluffing. Any aggressive action by you would simply see him fold, so by just calling you allow him to continue bluffing. You can call down on all streets, safe in the knowledge that you almost certainly have the best hand. But in almost every other circumstance continue playing aggressively yourself to have the best chance of winning big.
When thinking about bet sizing with big pairs the most important thing to do is strike a balance between getting maximum value (charging your opponent as much as you can) versus scaring them off (making the bet too big that they fold their mid-strength hands that you want action from). It's key to remember that you want action from opponents when you have a monster hand. This is why simply re-raising all-in with pocket Aces is a huge mistake most of the time (assuming stacks are deep) – you are now forcing your opponent to have a very strong hand to call you, whereas a smaller raise could have got called by all manner of hands you dominate, such as A-Q, 7-7 and 6-5 suited. If your re-raise only commits a small percentage of your stack – ideally, 20-25% - you also allow your opponents to believe that they could get you to fold. This means aggressive players could shove on you with weak hands as a bluff while you rake in the easy cash. Yet if your raise is too big then you eliminate this potential goldmine from ever happening.