It is a lot easier with experience.... but basically PA... watching the December & Jan NF and their respective change in Premium from Last week...to Spot helps....
Smart Money never waits for the last couple of days to Rollover.....If they are in command of the market without the participation of any Investment flow...then they will play the market as they please.... only thing that remains in the last couple of days for them...is their option positions......and they will do what needs to be done to squeeze the maximum out of their options....