As already said in English the conditional is widely used as expression of politeness. The same can be done in Spanish.

Wie im Deutschen auch, kann der Konditional auch als Ausdruck der Höflichkeit stehen.

¿Podría preguntarte algo? = Could I ask you something? ¿Podría ayudarme? = Could you help me.

No te lo aconsejaría. = I wouldn't advise it. (instead of don't do it!) Yo diría, que él tampoco sabe lo que quiere. = I would say that he doesn't know either what he wants.