I disagree with not setting trim prior to the go-round.
One tenet of learning research is 'primacy' ie what was learnt first tends to be what sticks. The upshot is that it becomes very hard to 'unlearn' a behaviour (or lack of it) so it's important to ensure that correct behaviours are established.
Even a Warrior or C172 can impose high control column loads if not trimmed, let alone when the pilot moves to other, less tolerant a/c.
I try to teach my students to approach each landing with have a general goal of trying to stop the a/c once on ground ie the goal of landing is to stop, not take-off. Only if they assess there is sufficient runway remaining, after setting flap & trim, are they to commence another take-off. They can always exit & taxi back to the threshold if they wish to take-off again. To me, the landing is important, not the subsequent take-off.
I agree with other's comments concerning the undesirability of accelerating while attention is focused elsewhere, reconfiguring the aircraft
I should add that aiming to teach this does not preclude always having a readiness to abandon this attempt at an approach & landing by going around. To this end, I teach that their hand should always be on the throttle, ready to apply power (apart from necessary times eg trimming, selecting more flap etc) and not removed until the likelyhood of needing an immediate power change is over ie the landing is completed.
[This message has been edited by Tinstaafl (edited 12 May 2001).]