Traveling light is the best advice for such an arduous trek. Breathable and thermal underwear will keep you comfortable and warm. Dressing in layers, such as fleece jacket, sweater, wind/water-proof jacket, and down jacket and vest, trekking pants will help you deal with the fluctuation of temperature during the trek.
Besides, the sun protection gears, warm headwear, and comfy trekking boots and a pair of trekking poles are also essential. You may also bring personal stuff, like toiletries, medicine and a vacuum flask for drinking and headlamp, etc.