You are running approach and a pilot requests Flight Following to your airport, but you are not sure of the path the pilot will use and how they will impact your approaches. So what steps can you take to help?
First, before you control approach, learn what all the runway fixes are. By doing this you can look at the FPL for the flight and determine which runway they are targeting.
Second, if it isn’t too busy and you know which runway they will go to, you can allow the pilot to fly their plan to that runway. If they are IFATC, you can feel mostly, not absolutely, certain that they will work to avoid other aircraft around. You may have to vector here and there if necessary.
Third, use ifatc.org and click on the plane in question in the Map view to see their intended route. With any luck, they will actually fly it.
Remember, it’s okay to say no if you are too busy. If I am vectoring fifteen plus aircraft into the runways, you will likely not get a proceed on course. Let me rephrase, you won’t get a proceed on course. I’ll try if I have less but if there is only one runway, limited approach vectors I can use, KASE comes to mind, then even less aircraft will affect my decision to say yes or no.
I have also found that pilots will request FF, but within 25 nautical miles they will then request ILS, GPS, Visual, Radar Vectors, etc. This is hit or miss though, sometimes you will luck out and sometimes you won’t.