If you express your request as a conditional -- "if you could open the window, that would be great" -- even though the content is an imperative, the fact that you're not using the imperative voice means that you're not acting as if you're in a relationship of dominance, where you could presuppose the compliance of the other person.
Ako svoju molbu izrazite kondicionalom: „Ako bi mogao otvoriti prozor, bilo bi to sjajno“, iako je sadržaj zapovjedni, činjenica da ne koristimo zapovjedni način znači da se ne ponašamo kao da smo u dominantnom odnosu, u kojem bi se poslušnost sugovornika mogla pretpostaviti.