If you use backdrops, the advice I give is to make sure you have enough lighting. You will want a bit of distance from the backdrop (depending on the backdrop), you will want to light up that backdrop pretty evenly to match the lighting of the subjects, and then lighting for the subjects. I even use small godox baby flashes to do rim lighting on the subjects to create some separation.
The same rules apply if using a green screen, but then make sure nobody is wearing green, or it makes post processing a bit more difficult. You put distance from the subjects and the green screen as to prevent any color bleed onto the subjects from the screen. One of the first mistakes I made in the beginning was having the green screen too close, and getting green tinting to shoulders, faces, etc.