Picture 1
I don't like the photo of the outside - the net curtain in the window above the front door was what I noticed first; I'd try and change what you have got in the windows and certainly get rid of the net curtains if you can.
Can you paint just above the front door? It looks like it needs doing (maybe that is just the photo) but it'd make the house look more looked after? First impressions and all that. Same with the window ledges, paint them so they are not different colours.
In all the rooms, put the lights on.
Picture 2:
Can you brighten the room up by adding some brightly coloured cushions to the sofa, maybe a bright rug as well?
Picture 3:
Sort out the curtains so they are the same on both sides of the window - either both tied back or both down. Can you put some flowers on the table, or the fireplace to brighten it up? Maybe a table cloth on the table? It looks a bit dark and drab.
Picture 4:
The kitchen does look a little dated but that can be put right. Can you put away any of the stuff on the work surfaces as they make it look smaller and like there is less space than there probably is. Can you empty the corner cupboard without the door and leave it empty to make it look like there is more space? Maybe just a small plant or something in there?
Picture 5:
Take the seat out of the bath and put something on the window sill to brighten it up. Also, some curtains or a blind would maybe make it look less severe? It's a good size room. Maybe have a chair on the raised up bit? I've always wanted a bathroom with room for a chair but that is just me 
Picture 6:
Move the clutter from under the bed so it doesn't make people think that there is not enough storage space
Picture 7:
tidy the curtains and move the boxes off the top of the wardrobe. Put a picture or a mirror over the bed?