As an ex ground crew, i used to find it fascinating watching how aircraft doors open/close. Their are quite a few different variations!
On Boeing aircraft for example (excluding 767 which use doors that lift into the sidewall/ ceiling cavity), the doors initaly lift out of the 'locks' (these look like liitle bolt holes all around the door frame) and move inwards slightly, the door then translates slightly towards the hinge and can then be pushed out through the gap it has just vacated. The door keeps rotating around the hinge until the door comes to rest, almost against the outside of the aircraft fusalage.
I stand to be corrected by someone more knowledgable in their operation . I have just put here what I have observed.