Make her laugh, that will impress her.
What's one small, subtle thing I can do with my place that'll impress a girl when I invite her over?
Make sure the towels in the kitchen and bathroom are folded/hung up neatly.
Clear a hook by the front door especially to hang her coat on.
have a good book/magazine/newspaper 'casually' lying round like they are what you were reading just before she arrived.
make sure the toilet seat is down.....
have a small throw pillow on your sofa / bed. She will move it to sit saying how uncomfortable they are (and they are) but we still like to look at them and they make it look like you are good with small accents like that.
If you're going to cook or make a drink of some kind make sure the things you need are at the front of your cupboards so you can just open it and take it straight out. No rummaging. Rummaging is un-organised and messy.
Hope that helps. It's what I'd like to see to make me impressed with a guys house. And its subtle like you haven't really tried.
Clean restroom is important, but you could cook something that smells really good