@Eleni219
I agree with @Anonymous that the lead photo is probably the first thing to think about. It needs to be good quality but also, one should think about which photo they choose to lead with. I have seen some hosts use a photo of the exterior of the house, others of an interior area and some use a photo of the local area. It really depends on what is the star attraction, e.g. if the listing overlooks a beautiful lake, perhaps the view is what will sell the listing rather than the interior.
As I host private rooms in a shared house, I always use a photo of the bedroom as I think that is what will be most important to most guests and the bedrooms themselves are attractive and probably better decorated/equipped than most of the Airbnbs in my area and therefore should stand out. If, however, I had quite basic bedrooms, I might choose something else.