This is a very good question with a very difficult answer.
Carlos Dinares explains how you can learn to place your footstretchers with the help of the Dynamic Erg RP3. Learning to place the footstrectcher correctly and how it should feel when is done properly can help you to row faster and better. This done right can improve your rowing technique and your rowing in general.
Also it can help you on your path to get a rowing scholarship.
Warm up 5 minutes easy rowing @ 20 stroke rate
Do 2 x 15 minutes (4′ @ 20 – 1′ @ 24 ) x 4 all the strokes with pressure!
Do 100 HARD STROKES 2x (20 strokes ON MAX pressure @ 22 – 10 str. Light x 5)
All the strokes ON are at MAXIMUM PRESSURE and the suggested stroke rate.
All the easy strokes are really slow (12 to 16 strokes x minute) with very light pressure.
Rest from 2′ to 5′ from piece to piece with some Light rowing. You can get out of the ERG.