I tend to suffer headaches, nausea and feel generally debilitated at high altitude, especially the first two days, but these suggestions really helped me be human and be able to hike at 8,500 ft from day 1. Some are from this site, some from internet. Best wishes to you if you're going up high and have had problems before, it's no fun to be out of it while everyone else in your party is having a good time. I did all of these things to leaving nothing to chance, and it worked!
1-2 weeks prior
Go all out in exercise like running or biking for several minutes most days, building up cardio vascular system. Any amount will help. I did bursts on my bike.
4-5 days prior
Start taking 120-180 mg Ginko Biloba per day
While at altitude
2T molasses per day
Homeopathic remedy Carbo Vegetabilis 30c or 200c – one dose daily
1000 – 1500 mg Vitamin C per day
Lavender oil – sniff or put a few drops in bath or back of shower
Ginger: liquid, tea or candy (I did tea)