Use your Fe. It's easy. It works. (It works because it's easy.) When you use Fe, everyone loves you, and you get happy. It is light, superficial in a good way, and fun. Don't try so hard on feelings. Just flow.
If you start having difficulties, you are using Fi, which is your default "id" function, driven by fear. It sabotages your relationships, making you look selfish and insecure. This serious feeling orientation is too heavy for an INFJ. It causes sadness, guilt trips, and anxiety. Leave it behind. Stop worrying that you will be "inauthentic" without Fi. Let it go. Play like a child. Others will find you inspiring, and they will follow you with smiles on their faces. Isn't that what you want? Harmony?
Read the article "Fe is Magic" by Blake of Stellarmaze.com. He's an excellent writer. Well worth paying the small Starling Subscription fee to read. Yes, this is a plug for his website, but I am in no way related to his operation.(It, and other articles can be found under Site Map>Fe Solution for the INFJ.)
I used to think I was an INTJ. I tried to use Te, but it was too rule-bound and objective. I tried to use Fi but it made me miserable. I figured out I was INFJ, and everthing started going smoothly. I cannot believe it.