Spleener- I used to ask at outer marker for rudder trim to be wound to zero whilst I froze my feet on the pedals to take the strain. The 737 training section persuaded me out of that, and I found it was actually better to leave a low trim setting in during the approach and then don't touch it. Rudder pedal forces can be very high, so no point in making too much work for yourself. After that you just watch the slip indicator (very poor) and the control wheel. As long as you centre the control wheel with rudder gently, the Flight Director will give you good indications. I can't remember the power settings very well.
Don't forget, when you land and come back to idle, you no longer have asymmetric thrust, so there will be unbalanced rudder trim suddenly yawing you into the live engine. Just a nasty little surprise when you think it's all over!