Breakfast buffets are my weak spot, I loooove breakfast foods. So I had to find a way to still have all that breakfasty goodness without wasting a days worth of calories. I follow the following rules to keep my calories low(er):
1) No seconds! I know it seems tempting and you feel like you're paying for it but you really don't need more than your first plate. Or if you really feel like going for seconds use the smaller plates they offer... not the full dinner size plates... for both "rounds".
2) Avoid putting butter/whipped butter/whipped cream topping
and syrup on pancakes and/or waffles. The batter often has enough butter in it already that you don't need to put it on top as well, especially if you have syrup.*
3) I'm not a huge fan of bacon and sausage (or any breakfast meat really) simply because I know how they're prepared

Stick with eggs for your protein.
4) Your plate should be half fruits and veggies (they're probably what you're paying for anyways - they're more expensive than the "bulk" sausages they serve you).
5) Try to avoid the pastries... I know, they're tempting. But could contain your entire breakfast worth of calories.
*Note about syrup: It has enough sugar in it that you really don't need anymore than 1tbsp... You can also try a low cal/fat/sugar jelly on your pancakes and/or waffles.
I hope some of these help you!

The biggest ones that help me are using the smaller plates and not putting multiple toppings on my pancakes and/or waffles.
Oh, and I should add that moderation is key... as you know... so don't not have anything if you really want it, just don't have a lot of it.