One way to guard your heart when you like someone is by being interested in them rather than being infatuated with them.
Interest occurs when someone is open to the possibility of a relationship with someone they like. Infatuation occurs when someone is obsessed with being with their crush. Interest is a willingness to give a relationship a try if the opportunity presented itself. Infatuation is being fixated on someone when you don’t even really know this person that well. Interest is when you try to get to know someone more to see if you connect. Infatuation is when you try to change yourself so that this person will like you. Interest is normal and healthy. Infatuation is idolizing a relationship.
Guarding your heart when you like someone is not about killing your feelings. It’s about navigating your feelings in a healthy, mature way that pleases Jesus.