They say it takes 21 days to break a habit, and you will have nothing like 21 days to practice in the truck!
Instructors are very used to the problems faced by deep rooted habits, they just slip you into a different habit, not exactly the best way to train someone but it gets the job done.
In my experience there are two types of instructors, those that teach do it like blah, blah, blah and give you little understanding as to why you need to do it, they use the phrase “the examiner wants to see you …” this method is technically poor but strangely it often leads to higher pass rate as the test suits habits - albeit the right ones.
Or the other type of instructor will teach you understanding, the driver will be more capable and safer but the catch is that this method takes longer, more explanations, demonstration drives by instructor, conversation/feedback from trainee, whats that you say, an instructor that will listen to you, not just bark orders, impossible that never happens!
Best advice is, they mark it as they see it, too slow is too slow, too late is too late, not applied is not applied, too close is too close, you get the idea.
Speed, do what feels right, if your personal speed sensor is not calibrated right you have a big problem!
Don’t do anything weird, the examiner won’t like surprises.
Steering, steer however you want, they will judge your ‘control’, spin the wheel at your peril!
Brakes, make it feel like you know how to use them to good effect.
Gears - not sure, we only use automatics now!
On your assessment drive the instructor should have judged your habits and how difficult they may be to adapt, so as long as you have got a long enough course duration for your habits to be changed you should be fine.
Funny thing is, Driving is one of the few things that you get worse at with more practice/experience! Take taxi drivers for instance, they are a challenge to adapt to test procedures!