Nice tips, will throw in my pointers. And that's from someone who has terrible hangovers (so much that I almost stopped drinking at all):

• Eat before the party, for sure. "Heavy" meals with some fat are the best (salad won't do you any good).
• Take some vitamin C before drinking as well, it will fire up your liver so they'll work more efficient afterwards.
• Drink water is a huge help. If you'll take a glass of water with each drink, you won't even believe you were drinking the day after.

But yeah, that one tip about cutting down the alcohol was probably the best. Stay with the weed all along ;)