The “vector” function is useful for this! If you activate vectors on all assumed aircraft in your sector you can toggle the number in the vector window to show the position of aircraft a number of minutes into the future. The end of the line is where each aircraft will be.
If you have a conflict developing, increase the vector length until the two lines of the aircraft concerned meet. You can then see the closest distance the aircraft will pass each other and issue a heading from there to turn one behind the other.
In AC sectors I usually keep the vector set to “1” to help me remember which direction the aircraft are heading and then I can use the tool as I need to look at separation if I need to.
If aircraft are turning at waypoints within the sector then obviously this method won’t work. Maybe issue headings and go from there.
