An easier way to line everything up is to make 2 marks 90 deg. off of each other on the cam sprocket. Then make sure you have the new belt tensioned like the old belt and you're good to go.

If you're doing the water pump, make sure to replace the pulleys and tighten the belts once after tightening the water pump down, but before you put anything else back on. You will think the pump is tight, but putting tension on the belts will align it better, and let you see exactly which bolts are now loose.