Quero is blunt at a counter. Portuguese softens a request with queria, which looks like a past tense but functions as a polite present, or with the conditional gostaria. Both are followed by a noun or an infinitive.
Examples
- Queria um bilhete de ida e volta para o Porto.
- I would like a return ticket to Porto.
- Gostaria de viajar em primeira classe.
- I would like to travel first class.
- Podia dizer-me a que horas sai o comboio?
- Could you tell me what time the train leaves?
The mistake to avoid
Gostaria takes de before an infinitive; queria does not.
Where this fits in
Deslocar-se, Portuguese A2: Mover-se na cidade e em viagem: transportes, indicações, hotel e bilhetes.