Don't think out loud.
I do this, and I think it has hurt the 4-some I've played with in the past. Some asks, "What's the distance on this hole?" and someone else says, "Oh, looks like 180."
And then I start going... "Ok. 180. But its a bit downhill. Lots of green behind the pin. Don't want to miss it short, cause of the bunkers there. Don't go left because the out of bounds runs along that side." etc. etc.
Those are my thoughts for my shot. But, if I say them loud enough, I know it gets into other people's heads. I've seen a guy pull out his 7i and then go back and pull a 6i, only to hit it over the green. I'm sure it had to do with my blabing on about "not wanting to hit it short". I'm training myself to keep my mouth shut. Even if they are good thoughts for MY game, its not fair to confuse others with my drivel.