Ian Clary at City of God links to an old series he wrote on “Reading and Error”, which gives some practical advice for those interested in pursuing the way of Reformed Irenicism. One quote he provides:

The best way to respond to erroneous teaching is to deal with the best of a person’s arguments, not the worst. Sometimes it can be easy to take an outlandish statement and punch holes through it. Little work is required and the desired effect of repulsion can easily be acquired. Rather, consider the strong-points, deal with them honestly, and it may be that the opponent is convinced by your godly response, but others reading your work may be drawn to your position. If you fail to do this, others will see and it will be easy for them to dismiss both you and your argument because of your lack of charity.