Following is a brief list of items advised for your Ladakh visit:

Dress / equipment:

1. Comfortable trousers, preferably of warm material (cotton or wool mix) and / or Jeans.
2. Thermal undergarments & sweat shirts / warm shirts (April-May & Mid September onwards).
3. A full-sleeved sweater.
4. Wind proof outer wear / jacket / parka, sun hat and a pair of good quality sunglasses with sufficient filter-factor to check the sun's ultraviolet rays.
5. A cap or balaclava (in case the weather turns bad especially in higher places such as Pangong Lake, Tsomo-riri, Khadongla etc.)
6. Comfortable walking shoes/sneakers with thick cotton socks (avoid fancy shoes/sandals).
7. For ladies: Trousers or Shalwar suite (worn over thermal inner or tights during April through May & September-October only), woolen sweaters / cardigans, a windproof jacket or a shawl, walking shoes with comfortable soles / sneakers (avoid sandals).
8. It is also strongly suggested to carry a flashlight on the tour. 
9. Miscellaneous:
1. All essential medicines, including those prescribed by personal physician (if any)
2. Sun cream, lip- salve, moisturizers, antiseptic creams, etc.
3. Medicines for altitude sickness and water purifying tablets, if required.
4. Altitude sickness: It's generally suggested to take one Diamox tablet a day for 3 days prior to your departure for Leh by air to be better prepared to overcome the effect of high altitude. But cconsult your doctor and confirm if you can take diuretic medicines like Diamox or Disprin tablets.
5. Visa and Permit: Tourists can visit Ladakh on a normal Indian tourist visa, and there's no need of any special visa or permit. However, foreign nationals are required to register themselves at the Foreigners' registration counter at Leh airport if travelling by air or at the check-posts at Drass, Rumtse and Sarchu if travelling by road. All tourists, domestic or overseas, are required to obtain Protected Area Permit / Innerline permit from the Deputy Commissioner Leh's office for visiting the restricted areas like Tsomoriri, Tsokar, Pangong Lakes, Dah-Hanou and the Nubra Valley. These permits are required to be obtained through registered travel agencies.
6. Non-local taxis: Taxis hired from outside Ladakh region are not allowed conduct any sightseeing or jeep-safari in Ladakh. Outsider taxis can only to drop the tourists at Leh or for return trip out of Ladakh. You Local taxis are to be hired for sightseeing and jeep safaris in Ladakh. There's no such restriction for traveling in personal vehicles.
7. Cash: for purchase of commodities or services or souvenirs. Credit card charging is uncertain due to frequent connectivity problems. Even ATM's are not very reliable or time-consuming due to the long queues, or shortage of cash in the machines. 
8. ATM: State Bank of India & J&K Bank has ATM points in Leh & Kargil town. Punjab National Bank operates an ATM point in Leh. These remain mostly crowded with long queues. Sometimes they also run out of cash.
9. Mobile Phone Service:  Mobile phones with post-paid connection of BSNL are operational in most parts of Ladakh. In Leh Town area postpaid connections of Airtel & Vodafone Networks also work fairly well.
10. ID Card / ID Proof: Remember to carry a valid photo ID card with you. This will be useful for a variety of purposes - identification at checkpoint, getting Innerline / Restricted Area Permits, Check-in at airports / hotels etc.
10. For Trekking / Adventure tours - If you are planning to go on a trek or any related activity, the following items may be required to be carried:

1. Ruck Sack: If you intend to go on a trekking or adventure trip, you need to get two rucksacks:  a smaller one for carrying your camera, water bottle, lunch box and space for change of clothes / jackets during the day. A bigger or standard sized rucksack is needed for packing your clothes and other accessories. This one should have extra layer of waterproof material for protection from rain etc.
2. Sleeping Bags: For travelling between June and mid September, light summer sleeping bag is enough. Warm winterized sleeping bag is required if you are travelling between mid September through May. You can also rent good sleeping bags from trekking equipment outlets in Leh.
3. Shoes: For trekking, you need to bring good quality waterproof shoes with strong sole for walking in the mountains and dirt paths. An extra pair of light shoes or sandals is will be required for crossing.