If you want to increase your feelings with your best friend, then I think you can start with the personality characteristics of your best friend. If your girlfriend likes traveling very much, then you can talk to her about the experience of traveling, or which place and specialty are better, which will increase the distance between you and make your feelings deeper and deeper. You can also accompany your best friend to do something she likes.

Or talk about something she's interested in. Many women are particularly interested in cosmetics or dressing up. You can share your experience in using a certain cosmetic, or what do you think of a certain dress, or talk about some luxury brands. This will make your relationship better and better, so it's different to talk to your girlfriends about which topics can increase your feelings.

It depends on each other's personality characteristics. If your best friend likes fitness and has a particularly cheerful personality, and you are introverted, then I think it is difficult for you two to get along, because she especially likes making friends, and you like wandering in your own world and don't want to share your happiness with others, then I think you two are particularly bored together.

Because people who are not from the same circle, if they get along hard, it will make two people particularly embarrassed. Therefore, if you want to enhance your feelings with your best friend, you must find a girlfriend with a similar personality, which will make your friendship particularly deep. Many friends around me like to go shopping with their girlfriends or travel together. When they get along, they will find each other.