Ok, so picture by picture:
Outside the front - clean the moss up growing along the wall, take a picture facing straight on and put a pot with a nice plant in it by the front door.
Room with blue sofa - vase of flowers on the hearth?
Room with stove - move the coffee table from in front of the fire - it looks daft - you wouldn't have it there with the fire lit, so it makes the viewer assume that the room is too narrow to easily walk past the coffee table if it is where it should be. Move it away completely if needs be, and remove the cardboard boxes from the side of the sofa - draws attention to a lack of storage. Raise the blind and take photos on a sunny day.
Kitchen looks fine.
Conservatory. Move the cupboard from in front of the radiator. Clean up the white marks (paint?) on the floor in the centre and to the left. Open the blinds and retake photos on a sunny day. Move furniture around to make the room look like it is used rather than a dumping ground. Sand down the uneven patches on the walls and give it a coat of paint.
Main bedroom - open curtains and retake photos. Do you have a plain white duvet cover? Would make the room look a bit less "busy".
Childs bedroom - open curtain and retake photos.
Bathroom - fab big room! Have you got some nice bright coloured towels to set off the grey / white?
Back yard - sand and paint the white woodwork on the right of the photo, add a couple of nice bright pots with plants in. Retake on a sunny day.
Grassed area - cut the grass, retake picture on a sunny day, get rid of the rubbish leaning by the bins, line the bins up neatly, get the gates hanging properly, clean the moss off the brickwork on the end wall. I'd also give thought to painting the brickwork to brighten it up.