For example, you are talking with a person who wants to support Obama because he wants to spend more on education, health-care, or something of the sort. Turn the attacks on Romney, over his record in Massachusetts, to advantage. Make your pitch on the inefficiency of having the Federal Bureaucracy intrude on concerns, traditionally handled at the State level--handled efficiently by Romney at the State level.
Even someone who likes more Government in our daily lives, can understand how wasteful--even with an eye at his, not your priorities--it is to add a very, very expensive layer of additional bureaucracy--moreover one which adds too many cooks to the preparation, calling up another point.
Put you argument in a non-aggressive, simply questioning what works best mode. In a certain percentage of cases, if you are able to gently introduce doubt, that doubt will grow, after you have gone on to work on someone else.
I have picked only one type of issue. But the method is adaptable to anything important to your target. For one taken in by the ACLU, for example, ask if he is comfortable with the way Home Land Security is being developed. Ask the "Liberal" if this is not disturbing, if even with a "saintly soul' (assuming that for the immediate purpose of reaching someone who may be that delusional) like Ms. Napolitano, he is comfortable with having a new agency with the potential role & fire power of a Gestapo? Again, put it in the form of a concerned question--without pushing your own opinion of the answer, in any sense aggressively.
William Flax
Bump to my own advice, which will actually work in some cases.