Two things to consider when first looking at a space: who is going to use it, and what are they going to do there. Spend time really considering this and have a clear picture in your mind.
Think about the user experience. We buy Apple products because the user interface is the most intuitive to use. It’s easy to learn, and feels natural. A well designed space should do the same thing. When you enter a space, you should understand the purpose.
Be Thoughtful, Details Matter:
Write out floor plans. They don’t have to be “to scale” but you do need to account for every inch. The devil is always in the details and often a few inches can make or break a decision. Make sure windows are centered. Trim, knobs, fixtures all must match. People notice when they don’t.
And one “off” thing has a psychological effect. Like a thread that you pull at, if this one thing is wrong then what else might have had a short cut taken? What else did they miss?
What happens when you have a properly designed space is that it elicits the feelings of the room’s intent. A living room feels like a place to relax. A kitchen feels like a place to cook. There are no annoyances that get in the way or impede these activities. There is flow.