Lots of people missing the point a bit here, it's fine to say you'd never buy a house with no parking or with small/awkward rooms or on a busy road or whatever but I think OP is looking for tips on things she can change!
Personally OP I can look past pretty much anything in terms of smell or appearance/presentation of the house as I am pretty cold/unemotional about it so am really just looking at the fundamentals of size etc, but from my experience of selling houses a lot of people go a lot more by how the house 'feels' and want it a bit more 'staged' for want of a better word so they can imagine themselves living there. Also people who haven't done much work to a house can get a bit paranoid that minor jobs like redecorating to their taste will cost ££££ and take ages and this can put them off, so unless your house is a total fixer upper it's worth making everything seem neutral and 'move in ready'. I wouldn't spend a lot of money as in all likelihood you won't see it back when you sell but do:
-Have a massive tidy and declutter - lots of stuff everywhere even children's toys etc in a family house can make people feel it lacks storage and/or is too small. When I was selling a place that genuinely was small I used to fill up my car and garage for every viewing with stuff that normally lived in the house plus dropped off some lesser used stuff at my MIL's for a few weeks to give more impression of spaciousness.
-I've give the garden a good tidy and weed, if you have or can borrow some nice patio furniture to put in the sunniest spot that would good, maybe give the fence a lick of wood stain to smarten up? Put some nice pot plants around the place for colour.
-Make sure everywhere is clean and smells good, personally I think it's ridiculous to not buy a place because it smells bad, even a hellhole which has been damp or lived in by a chain smoker or 100 feral cats, never mind just the 'normal' bad smells of everyday living can be made to smell fine with a few days solid airing, replace carpets and thorough clean but I am 100% confident there are people who won't buy a place because it smells 'off' to them, I think even sub consciously it affects what they think of it and how at home they feel. If you can try and make it smell of something natural and nice - clean laundry, fresh bread, coffee, freshly cut grass, that kind of scent as opposed to unnatural heavy air fresheners.
-Any minor DIY jobs like dripping taps, chipped or damaged painting, cupboard doors loose should be fixed. Again you may think these are so minor why bother fixing them but it just gives the impression of a place which isn't well looked after and can worry people it's a 'tip of the iceburg' situation.
-Make sure the photos on your estate agents website/right move etc are taken in good light, flattering angles and show nice uncluttered rooms 'set up' in the way you are saying them can be used, e.g. if a room is marketed as a bedroom it should have a bed in (ideally a proper double bed if it's a double room although appreciate if it's a childs bedroom at the moment that may be difficult), if a dining room should have a dining table and chairs etc. Half the battle is getting people through the door! Don't be dishonest though e.g. implying there's off road parking when there isn't as this will just piss people off looking at you my last estate agent--
Good luck!