Items to bring
Poncho or light rain jacket (weather can change quickly at high elevations)
Bottle of water (one will also be provided for you)
Good hiking shoes... closed toe is suggested, but on some of the easier hikes shoes similar to chacos would be fine.
Try to wear clothing made of nylon/spandex/polyester that dry out quickly… cotton holds moisture longer than any material.
Most hikes are probably 80% shaded, but if you burn easy sunscreen might still be needed.
Insect Repellent if you tend to attract insects… I carry an all natural cedar oil repellent with me, but I rarely have to use any.
Most importantly, bring a smile and be ready to have fun enjoying the wilderness of the outdoors.