Sure, Itanagar, Tawang, and Ziro are incredibly beautiful places which are a part of North-East India's beauty. Here are some travel tips for your journey:

Best Time to Visit:
The best time to visit these places would be from October to April. During this time, the weather remains pleasant and good for sightseeing.

Route and Accessibility:
Itanagar is accessible by air, rail, and road. You can land at the Itanagar airport or Naharlagun railway station, and then hire a taxi or bus to reach your destination. For Tawang, and Ziro, road travel is suggested after reaching Itanagar.
Roads from Itanagar to Tawang and Ziro are well connected.

Altitude and Acclimatization:
Tawang is situated at an altitude of about 10,000 feet above sea level while Ziro is around 5700 feet. You need a day or two for proper acclimatization to avoid high altitude sickness.

Accommodation and Booking:
There are several options available ranging from luxury resorts to budget hotels and homestays in these areas. Online booking is available on various platforms.

Clothing and Essentials:
Depending on the time of year, carry light woolens for summer and heavy woolens for winter. Do not forget to carry comfortable shoes, umbrellas, and raincoats as it often rains here.

Health and Safety:
Ensure you're carrying a good sunscreen lotion to avoid sunburns. Carry necessary medical kits, keep yourself hydrated and eat healthily.

Local Etiquette and Respect:
As always, respect local traditions and customs, be polite and ask for permission before taking people's photographs. Dress appropriately when visiting local religious places.