She will always countdown to when next she will be with you.
1. A unique experience
Give her an experience that she can remember only you by. But be unique with the experience and you can even make it something she has never done before or something she has always wanted to try but just never got around to it.
2. Do other things
You do not always have to be with her. Hang out with your friends, pursue other interests and encourage her to do same. Being her boyfriend does not mean she has to be tied to her apron or her to yours. Give her an opportunity to actually miss you.
3. Send her a song that is special to you
This is one of the most romantic ways of making her miss you. Just send her song that she knows is special to you and the lyrics should hold some meaning. In time, the song will become 'your' song, i.e, a song that means so much to you both. And before you know it, hearing that song anywhere will remind her of you all the time.
4. Make her laugh
You need to realise the importance of giving up your hard guy stance once you get into a relationship. Being unemotional, or deciding to bury that side of you underneath is not ideal. If you want your girlfriend or babe or wife to miss you and constantly want you by her side, make her laugh as many times as you can. All the time.
5. Treat her well
If you treat her well, give her unrivalled and undivided attention, she will always feel special with you, and will associate that feeling of being wanted with you. As a result, she will always want to spend time with you and when she can't, she will pine so much for it.