Why full power? Why not select cruise power - ok fixed pitch propeller you'll have to set a tad more (50 rpm?) as the rpm will increase slightly as the speed increases.
Yes the initial attitude required will be that which is appropriate to fly at 70 kts - as the speed increases you will need to progressively lower the nose to maintain height (technically the student should know how to do this as he has already been taught straight and level flight at different airspeeds, hasn't he?).
Would teach a coarse trim initially and then fine trim as the speed stabilises.
An airspeed change of greater than 20kts technique:
Let's say you're at 1800RPM, 70kts s&l. To increase speed to 100kts in s&l you increase to full power, then anticipate 5kts before 100kts (at 95kts) select 2200rpm (which is supposed to give you 100kts s&l).
The reason of this extra burst of power before reducing it is to make the airspeed change faster.
shumway, agree but that assumes that you
want to achieve target airspeed as quickly as possible - I believe CFS teach both techniques - ie slow/fast acceleration (and also slow/fast deceleration)