Cut down on your amount of ~decorative~ clutter.
Make sure your lighting is A+.
If your home doesn't get much sunlight, invest in lamps and string fairy lights.
Use mirrors to create the illusion of bigger rooms.
Find storage solutions that make use of your doors.
Make your bed each and every morning.
Use temporary hooks to hang things, drawing your visitor's eyes upwards.
Buy a bed with built-in storage.
Make use of your windowsills.
Or create a faux windowsill using a low bookshelf.
As the seasons change, pack away things you won't be using for the next few months, like beach towels and big coats.
Use your oven as a storage space.
Use an ottoman or leather pouffe as extra seating when you have guests over.
You can even store it under your coffee table when you don't have visitors.
If you don't have room for a coffee table, buy plain stools that can act as one when they're not being used as seats.
Glass or perspex coffee tables can also be a great choice for small spaces.
When choosing a dining table, go for one with bench seating.
If you don't have enough cupboards for all your food, use containers to make whatever doesn't fit look neat.
And add temporary shelves to your kitchen bench for extra cooking space.