Rent a storage space. Put everything that doesn't make the house look better there for the duration. Be brutal, because if you have lived there a long time it will be more than you think. Things such as too many mugs, bulky cake tins platters and pans will give the impression that the kitchen isn't quite big enough. Ditto wardrobes and drawers.
Agree with Lonecat - it's time to stop thinking of it as your home and think about it as a marketing project.
Think of how houses in magazines or new housing development brochures look. Clear surfaces, smart toiletries, not too much furniture etc. You want to give the impression that the house is spacious with PLENTY of storage space and people living there will have a lovely lifestyle ever so slightly above whatever would be normal for the price bracket/area.
I have a friend who does up houses in her area to flip and having tried a number of different approaches (empty/fully furnished in different styles/partly furnished etc) now she always stages them for sale with small, contemporary generic type furniture from specialist staging companies which she says way more than pays for itself. Even if you can't justify the cost of professional staging have a look at some websites to get a feel for their style. If you have furniture that doesn't work then think about renting/borrowing an alternative for one or two pieces. Buyers aren't interested in how comfy the extra large sofa is, they will just see a small room where you have to squeeze past the coffee table to sit down or that the door doesn't open fully. If your pictures are very personal in taste take it down or replace some with a mirror. Ditto if you have loads of family photographs. People need help to imagine themselves and their things in the house - if it's full of your stuff not everyone can see past it.
Clean like a crazy person. Clean windows inside and out. Air, air and air some more. Clear out underbed spaces, understairs or anywhere else you store things. We got a commercial cleaner in for half a day and it made a difference because he cleaned places I had never thought about.
Be aware that we all have blindspots, personal tastes etc and that buyers will see negative things where you don't. Ask the estate agents for their critical opinion. Be aware that most people will shy away from telling you negative but truthful things about something as personal as your home, so you have to really make it clear that you want to be told. If more than one agent tells you that painting a particular room or replacing a carpet, removing some furniture will make a difference then trust them and do it.
Be a bit sceptical of the prices the agents suggest and understand pricing strategy. You don't want to market far above what the house is worth because some buyers will rule themselves out and won't put in lower offers so you might end up getting less than from a slightly lower marketing price with the house going for more (depends a lot on the current market conditions where you are selling). Agents want your business so they may just tell you what they think you want to hear which is that they can sell it for loads. Ideally you want a situation where more than one keen buyer wants your place and they are competing for it.
Interview agents - a good one is a rare find and could make you thousands more. Get someone to be a secret shopper by viewing similar houses to yours that the agents have listed and see what they think of the service. How long is it taking the agent to shift the houses already on their books? Get someone to leave details with agents in the running along with a spec of what they are 'looking for' and see how long it takes for someone to call you back and propose some viable options. I spent a month pretending to be interested in buying a house and I was stunned by the varied level of effort put in by different agents, even within the same office the quality was varied. Some simply facilitated buyers entry and expected houses to sell themselves the best actively sold houses while others were too pushy. Human nature dictates that people are quicker to buy from people they like and can identify with so it matters that your agent is pleasant and friendly and not weird! Check that the person you agree terms with will be the person handling the sale.
Good luck!
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