Here's something you guys need to know about most girls.
1. If you're talking to her day and night, remember before you do this, you have to be sure you wouldn't suddenly leave her alone. That would break her heart.
2. Don't flirt with other girls
3. Don't make promises you can't keep
4. Send her cute texts occasionally, this will make her day
5. Be honest and always be there for her, because she's doing exactly the same to you
6. If you lost interest, don't try to make her stay anyway, tell her indirectly and let her go. It is not fair at all for someone to stay with a person who doesn't like them anymore. Don't waste her time.
7. Treat her right guys.