If you have pets, there are a number of specific things that need to be taken care of to 'de-pet' your property before it even goes to market.
Removing the evidence will be your biggest job. There's no need to throw a camouflage tarp over a kennel, or cover the aquarium with an elegant throw rug, but the standard objects that come with pets should be taken care of. This means water and food bowls, DEFINITELY kitty litter trays, bags of pet food or litter strewn across the laundry, dog beds, cat keepers and so on.
Your house will inevitably also need a deep clean. Urine stains and hair specifically are non-negotiable, on furniture, beddings and curtains, floors.
You may think a standard vacuum will deal with this, but if a potential buyer has allergies and there's a deep layer of hair or animal dander your vacuum hasn't picked up - you will know about it and fast.
Once you've cleaned everything, the next job is to get rid of their smell. When you live with a pet for a long time, you become desensitised to their smells. Long dormant odours from decades of pet habits can be difficult to deal with and this is when you bring the big guns in - the steam cleaners, the florists, the oil burners and the smelly candles.
A thorough carpet cleaning will make a big difference and if you have any suspicion of fleas, you should have the place treated just to be sure.