Hello! Wonderful to hear about your plan to visit Berlin, Hamburg, Dresden and Leipzig. These are beautiful cities in Germany with lots of cultural and historical significance. Here are some useful travel tips for you.

Best Time to Visit:
The best time to visit these cities in Germany is during the late spring and early autumn, that is, from May to early October. During these months, the weather is pleasant and perfect for sightseeing and outdoor activities. The festive seasons around Christmas and New Year are also exciting times to witness traditional German celebrations.

Route and Accessibility:
Germany is well-connected by flights with major cities around the world. From the airport, you can use Germany's efficient public transportation network. Berlin, Hamburg, Dresden, and Leipzig are all easily accessible by Deutsche Bahn trains and Autobahn highway. Within these cities, public transportation like U-Bahn, S-Bahn, trams, and buses offer convenient mobility.

Accommodation and Booking:
Accommodation options in these cities range from luxury hotels to budget-friendly hostels and vacation rentals. It's advisable to book your accommodations in advance, using reliable online platforms like Booking.com or Airbnb. For an immersive experience, you can also consider staying in guesthouses or 'pensions'.

Clothing and Essentials:
Due to variable weather, it's best to pack layers. A rain jacket and waterproof shoes are essential, as rain can be unpredictable in Germany. Also, don’t forget your power adapter (Germany uses type F plug sockets) and a travel guide or dictionary to help navigate and communicate.

Health and Safety:
Germany is generally a safe country to travel to. However, it's always a good practice to have travel insurance. Emergency services are reliable and readily available. Carry a basic first-aid kit for minor ailments and if you have any existing medical conditions, ensure you bring your necessary medication and prescriptions.

Local Etiquette and Respect:
Germans generally appreciate punctuality, respect for privacy, and being greeted with a nod or firm handshake. Always remember to maintain cleanliness and respect local rules, especially in public places.