Sporting shoes or comfortable walking shoes are highly recommended for all weather. Also, don't forget to bring along pile jackets, wool or wool mix sweaters with high neck, wool or silk scarf, mittens or groves, cotton underwear, long sleeve shirts and loose fitting pants. Journal, reading book, writing materials: For quiet moments.
Camera: You will regret not bring one. Binoculars: Good for observing birds, wildlife, and distant scenery. Money pouch or belt: Safer than a wallet for keeping your passport, money, and valuable papers.
Pictures from home: Personal photographs of your children, pet, city, house, and so on are a great way to communicate with local people. Snack foods: Nuts, chocolate bars, granola bars, dried fruit, hard candies, beef jerky, and flavored drink mixes are much-appreciated trail treats.
As to the equipment for trekking, your tour operator will do the big work for you, like the tent, cooking equipment, food, car, truck and pack animals etc. Even these facilities will be arranged by the company, you still need at least 2-3 months to prepare for your personal packing. When planning your clothing needs for a trek, think in terms of layers. Layers of clothing will keep you warm, but can be removed to gradually prevent overheating. During spring and autumn the night temperature in the mountains often dip below freezing, making warm gear essential. In the summer the days can be hot, requiring light cotton clothing. Adequate wet-weather gear is also a priority during the summer. Remember that the mountainous regions of Tibet can receive snow any month of the year, and always be prepared for cold weather if you will be trekking at elevations much above 4880m. Make sure that the clothing you will wear most often can be washed in cold stream water and dries quickly.