Hmm...
Fi is all about personal subjective feelings. Feeling is directed inwardly. So, for me, this tends to equate to over-sensitivity. I'm also more in tune with my feelings since I am an Fi (Introverted feeling) dominant type: ISFP. When I interact with others, I tend to think about how the interaction made me feel. I can also turn it around and feel empathy for others by putting myself in their shoes. I'll tend to be cordial and kind in my interactions because I want to keep my internal peace and I'd want the person I'm interacting with to maintain their personal peace.
Fe is a little different, and less familiar to me. Feeling is directed outwardly. My understanding is that their feelings are associated with norms and how one should act or respond. It's more outgoing and less focused on the self. (You'll have to get someone else to explain it better.)
Se is focused on external sensory data. This usually boils down to the five senses. The world is concrete and based on what one can taste, smell, see, feel, hear. People who use this as their dominant or secondary function tend to be artisans of some sort. Artists, painters, chefs, athletes, musicians, dancers, race car drivers, mechanics, and so forth. The world is manipulated by their hands and their body.
For Si, the world is concrete and based on what works. Si types tend to be more orderly. Where Se tends to enjoy working with their hands to create a fluid rhythm, Si hands works from memory.