Hello! It's great to hear you're planning a trip to Hradec Králové, Olomouc, and Ostrava. Here are some useful travel tips for you.

Best Time to Visit:
The best time to visit these Czech cities is during the late spring (April to June) and early autumn (September and October). The weather is particularly pleasant during these periods.

Route and Accessibility:
Hradec Králové is well-served by public transport, with a robust bus and train network. Olomouc and Ostrava are also easily accessible by train or bus from other Czech cities or from neighboring countries. If you're beginning your trip in Prague, you can reach Hradec Králové in about two hours by train.

Accommodation and Booking:
You will find a range of accommodation options in these cities, from luxury hotels to budget hostels. If you're travelling during the peak season, it is advisable to book your accommodations in advance. Booking.com, Airbnb, and local Czech booking sites can be useful for finding and reserving your lodgings.

Clothing and Essentials:
Meteorological conditions can be quite changeable in the Czech Republic. Ensure to pack for a range of weather conditions. If you are planning to visit in summer, pack light breathable clothes, a hat, sunscreen, and comfortable walking shoes. In the colder months, warm clothing, a good quality jacket, and sturdy shoes are necessary. A good guidebook, a Czech phrasebook, and a power adapter for Czech plug sockets would also be useful.

Health and Safety:
The Czech Republic is generally safe for travelers, but you should always take common precautions such as keeping your personal belongings secure, having a copy of your passport, and knowing the location of the nearest hospital.

Local Etiquette and Respect:
Czech people generally value politeness and modesty. When entering shops, restaurants and public places, it's customary to greet people with a polite 'Dobrý den' (Good day). Try to remember to say 'Děkujeme' (Thank you) as a sign of respect. In general, avoiding loud or boisterous behavior in public places is appreciated by locals.