GOTV: Am I just really bad at it?

I have canvassed for three elections now (CA 2002, NA 2004, CA 2005), and each time I spend 8 hours a day for several days going door to door, I feel like I changed few minds and made little difference.  The houses where I tend feel the best are those in which the resident is very pro-democrat already -- it's just a relief to talk to someone who understands the issues after a day of otherwise.  The worst is when the resident remains unconvinced that politics affects anything in their life.

And I always leave the day thinking, did I find 4 new votes today, or maybe I found 5.

I've been recognized as a good teacher (I am a grad student at UC Berkeley and teach math to undergrads), so I should know how to communicate and connect to people reasonably well.  But somehow either I am, or just feel, really bad at canvassing.  

Phone banking is no better.  A million answering machines and 10 real conversations later, I'm thinking, did I find 2 votes today?  Well, maybe I raised this guy's probability of voting for Kerry from 37% to 43%.

So first, I'm asking for suggestions about talking to people.

I also feel like most organized GOTV (e.g. through unions, etc.) is more interested in knowing what each voter is planning on doing on election day than on changing minds.  Is this worth as much as they seem to think it is?

I remember going into a grocery store with my companions in Nevada 2004 and talking to a random woman watching TV.  She had no idea what was going on politically, and we engaged her in conversation.  It seemed like she might actually take some of the information home with her, and even disseminate some of it.  That felt like a success.

So second, I'm asking if maybe there are better ways of changing minds than through door-to-door canvassing.  Canvassing involves interrupting someone in their home.  Whatever they were doing, they are going to feel like it's an intrusion, especially if they're in a swing state and hit regularly.

Today in Thailand, thousands of protesters went to the shopping malls to bring their feelings about the Prime Minister to the shoppers.  Is this better?  Is it just a different type of interruption and intrusion, which leads to people trying to get rid of you; or does it create a stir that gets people at least talking about the issues; or does it create a stir that gets people annoyed at the very cause we're trying to promote?

Maybe our success with the woman in the grocery store was more based on its spontaneity or her particular receptivity than from its occurring outside of the home.

This is probably the kind of stuff taught in DFA school, but I haven't been (too busy with my dissertation), so help me out.

If you have any suggestions, or if you have the same problem as I do, recommend this diary, because I think there are a lot of people who feel the same way I do.  And it's quite discouraging.