Relationship is always a hard thing and you need to be prepaired for this. Relationships are based of understanding and love. And these are the main things, that can keep you two together. Although common interests, in my opinion it's very important to have at least 2 or 3. You don't have to share everything. Because in every relationship you need to find something new to you. Find out about a new movie or a book, a new place to visit or a new game to play.
If you ask me, what my ideal girlfriend is like, I would probably say kind, caring, understanding and clever. Her beauty would be a perfect bonus, of course. As I said, we can have mutual interests, so we can spend time doing something together and both enjoy it.