Maximise attic space

Finishing an attic is a great way to add an extra bedroom or an office to your home. But even if your attic isn’t well suited for that, you should still utilise it for the storage space. The key is adding shelves and other systems that can help you organise it, rather than just randomly jamming your extra stuff into attic storage.
Use dead space in the bathroom

There’s a lot of empty space above your toilet, in between the shower and the sink, and even above the door. Chances are even if you’ve got a small bathroom, there’s perfectly good space in there that’s not being used to its fullest. One built-in storage option to consider is building a medicine cabinet into the stud cavity of the wall. That might not be an option if you’re renting your place, so if that’s the case, you might check with your landlord to see if you can install a larger, surface-mounted medicine cabinet.
You can buy storage solutions for your bathroom too, like a cabinet that goes over the toilet to provide lots of storage space.
If you’re trying to give the impression of a bigger bathroom, you could paint the cabinets the same shade as the walls, or consider tiling the area if your tile shape and size permit.
Use bunk beds

If you’re short on space, why not take only half of it by building in bunk beds? This may work better for kids than adults, but it can still be fun and grown-up. Depending on how you build them, you can create clever extra shelving within the structure too, on the side or set into the wall behind the pillows.
A woodworker should also be able to incorporate a couple of roomy drawers beneath the bottom bunk to make even more use of the space.