Over time, I have realized that debates, especially related to Vedanta, are in vain when those involved in the same have no formal training in logic, especially Nyaya. As such, there is no fundamental agreement as to what is an accepted common ground among them! The entire idea of the debate in the Vedanta texts is to establish the सिद्धान्तः for the benefit of everyone. If nothing, it should serve as a मनन to one's own progress in clarity of understanding. That being the case, one cannot start with the discussion having concluded on the subject one way or the other. Just because "I think so" or "I don't agree" seem to be very valid statements, whereas they are not, unless there is a basis that supports these statements. On what basis one thinks the way one does has to be established with a concrete support from scripture and/or scriptural logic. In the case of Vedanta, श्रुतिः and/or भाष्यम् is a clinching argument. If one doesn't understand what is being said, one can't resort to simplistic resolution such as सर्वं खल्विदम् ब्रह्म, since its plain escapism or shirking your responsibility of participation in the debate in the first place.
The very process of development of the debate or even an understanding of what makes up a debate is amiss to most people of the category described! That one changes one's initial stance during the course of the debate is a clear indication of such illiteracy of basics of logic. This is why traditional Vedanta insists on training in न्यायशास्त्रः and पूर्वमीमांसा prior to one embarking on Vedanta. It is not for no reason that Vedanta is called "उत्तर-"मीमांसा!
One of the very common flaws I have heard is the overuse of the word मिथ्या for everything except what suits one's argument. It is to be clearly understood that everything, including the pursuit towards liberation, including the debate-- nay, liberation itself, is *only* in the sphere of मिथ्या! From the पारमार्थिक, there is nothing other, let alone a debate!!
For a debate to be fruitful, one has to be clear about the प्रतिज्ञा that is the point one is trying to establish, clear statements leaving no ambiguity, no contradiction with earlier points, unless one withdraws the same, no interruption during the examination of one's stated view from the other and during the latter's response that follows, which also necessarily needs the same level of clarity.
Personally, for me, a debate with a learned person is a learning experience. It is not an argument to win over. It is मननम्। And to that effect, may we all who share this view be blessed with मननम् to fruition.