Absolutely! Traveling to these beautiful European cities will certainly leave you with memorable experiences. Here are some travel tips for your journey:

Best Time to Visit:
The best time to visit Barcelona, Nice, and Venice is during the spring (April to June) and fall (September to November) when the weather is pleasant and the crowd is less.

Route and Accessibility:
All three cities are well connected by numerous airlines. You can plan your journey starting from Barcelona, then flying to Nice and lastly to Venice. Internally, all these cities have good public transportation like buses, trams and metros.

Altitude and Acclimatization:
These cities are at sea level, so altitude sickness is not a concern.

Accommodation and Booking:
Book your hotel accommodations well in advance owing to the popular demand. All these cities offer a range of accommodations from budget to luxury.

Clothing and Essentials:
Comfortable walking shoes are a must as these cities have numerous sightseeing spots best explored on foot. Also pack clothing according to the season of your visit. It's always advisable to carry a raincoat or umbrella.

Health and Safety:
European tap water is safe to drink. However, stay updated on any local health advisories. Personal safety in these cities is generally high but beware of pickpockets in crowded areas.

Local Etiquette and Respect:
While Europeans are known for their friendliness, always maintain decorum at public places, respect local traditions and be aware of any specific local customs. In Venice, avoid picnicking or littering in public places to respect the city's efforts to maintain cleanliness.