Choose elements that switch-hit. Find a table that can function as both a desk and a dining table. Get daybeds or deep sofas that can double as guest beds. A storage ottoman can provide an extra perch, a little table, and a secret hiding place.
What a gorgeous loft-style bedroom. I particularly love the whitewashed exposed brick walls and the low-lying mattress bed. The addition of the slim staircase leading to a tiny dressing space is just gorgeous and such a great use of space.