Fill a glass half full with fresh orange, a pinch of salt and top up with water and neck it.
Also coca cola throughout the day helps.
In terms of food - anything goes, just load it up. The distraction of eating usually helps.
Could also opt for what I'm sure Johnny Vaughan termed the "Nurofen Blast", set your alarm for 6am, drop a couple of nurofen and drink a few swigs of water, hit the hay again and wake up several hours later feeling fresh. Has always worked a treat for me.