Altitude is no joke, so, cudos for wanting to prepare.   Great tips here so far here.  I'll add ..start drinking water a day or so before your trip.   Also, once on your trip,  listen to Your body and don't be influenced by the group.   Have a plan B (like 2 cars) if you or others in your group need to go back to lower elevation.  Lower elevation is often the Only solution.  Carbs- often overlooked is that your body metabolizes carbs differently at high altitude so carry quick carb snacks always, and be well nourished especially the night prior to a big hike day.   I also carry electrolyte powder or tablets in my pack.  I don't use them always in my water because I drink as much if the water is flavored, but break out the electrolytes when the body feels extra taxed.