WEAR PERFUME! It may be out of character for some of you but it leaves a memorable impression on your guy that will be there even after you've left.
You want proof?
I went to my boyfriends house today and made sure before I left to put on my favorite perfume. We shared in our first kiss. Right after I got home he instant messaged me to talk as we do every night, one of his first comments? How good my perfume smelled and how he loved that he could still smell it on himself. To make it funny? Later in the conversation he informed me that his dad had asked why their couch smelled so good.