We've moved into a rental whilst our building work is underway. It was absolutely filthy!! We've spent 25 hours getting this place clean (it's a small 950 sq ft house!!).
First, I emptied all furniture from every room. I put everything except the sofas into the garden and hoovered the living room floor. I cleaned every skirting board and radiator. Then I cleaned the light fittings and windows, as well as mirror and framed pictures. For the curtains, I had to make do with a light hoover and febreeze.
Then I mopped 4 times till the water was clean!! Then I cleaned every piece of furniture as I brought it into the house.
I replaced the filthy rug (rolled and put under the stairs) and replaced it with an IKEA one that is clean and fits perfectly.
Just the living/dining room took 6 hours!
The downstairs toilet and upstairs bathroom were easy to clean. Again, everything needs to come out. In my case, I put the landlord's toilet brushes and bathroom bins under the stairs and bought cheap replacement ones from Asda. I already asked him to remove all of his towels, bedding etc.
For the bedrooms I hoovered the mattresses, washed the landlord's protectors and put them back on the beds and put my own protectors on top. Then I've used our own duvets, pillows and covers. Also, cleaned all of the skirting boards, light fittings and windows. Scrubbed inside drawers and wardrobes.
I hired a Rug Doctor to clean the stair carpet and bedroom carpets. I was able to shift all of the furniture out of the bedrooms, except for the beds, so I worked around those. I also use the machine to clean the landlord's fabric sofas and chairs in the living room. I bought cheap throws from Primark to cover those up after they dried.
The kitchen needed a deep clean inside every cupboard. The skirting boards and door fronts were dirty too. I then selected what I would use from the landlord's stuff and put it on a hot dishwasher cycle!! I made 2 corner cupboards "out of bounds" for the kitchen stuff we won't use.
Finally I stored the landlord's dirty doormats and bought cheap new ones from Asda.
In the utility room (such a dirty gross floor), I removed the floor mats and put down some packs of sticky floor tiles from Poundland (total cost £4). I'll take them up when we leave and I've got a stick residue cleaner if there is any sticky stuff left.
So in summary, you need to make sure you have all of the cleaning products in advance (hoover, mop, bucket, bowl, lots of packs of clothes, Flash floor cleaner, multipurpose Cif cleaner, toilet bleach and rubber gloves).
Make sure you empty each room of all furniture as much as possible. If you have lots of ornaments etc, use a laundry basket to collect and store.
Good luck!!