They usually will be 3/4 star, and just take notice of who gifts you, also be proactive.. When I visited a neighbour I would say if possible please can I have basic parts or food or whatever you would like, and then ask what would they like too, and I wrote down all of my neighbours names and then for a week I marked off who gifted me each day, then its easy to see who is active.
I personally dont do the main goal, so I only gift food or basic parts, when I add someone I check which one they want and make a note too,only a couple of my neighbours do the main goal, most like to be sent basic parts and a few like food, you just have to find your people. !