If you are landing in El Prat airport, the fastest way to get into the city is the Aerobus. It leaves you in Plaça Catalunya, and from there your accommodation should be easy enough to get to. A return ticket is just over €10 and definitely the easiest way to commute in.
🚕 Getting around the city
Official taxis in Barcelona run on a meter, so there’s no chance you’ll be ripped off. Look for any yellow and black taxis, and look for a fluorescent green light which means the taxi is empty and available for you.
You can also try downloading the app FreeNow (a little bit like Uber).
Most attractions are within walking distance of a metro or tram station.
You will find your way around the metro very quickly. If you have a specific destination, look for the nearest metro station and see which line goes there and what the terminus of the metro line is called.