Instructors are good, in that they tell you exactly what you need to do in your test to pass. My weaknesses were smoothness at the roundabouts (indicating in/out. I use to steer in, then take a hand off the wheel to indicate in/out which will probably fail you in the Ps test), and I use to steer in a "illegal" way (put hand inside the wheel) which is what my dad does and still does.
But get a few lessons at the beginning to build on what you are suppose to do. Then a few lessons right before your test. (so you are warmed up and ready)
With me, it was hard. I learnt alot of bad habits, and had to spend alot more in the lessons preparing for the upcoming ps test.