Play before thinking
lavalyn: At least until 25k (and probably closer to 5k) prolonged thought at a position doesn't mean much. You're likely to be thinking about the wrong things anyway, and in this wonderful game the reading depth requirements to do raw analysis can get enormous and unreasonable very quickly.
So play out what are basically blitz games, developing a basic sense of what works and what doesn't. Eventually you will stop making 30k mistakes like cutting bare on the second line and such.
Charkysan?: "Playing without thinking" assumes that the only thinking (that counts as thinking) is reading a sequence out completely and analytically. Actually, there are many other kinds of thinking a player can use, such as partial reading, pattern recognition, intuition, creative inspirations, habits of personal style, offensive impulses, defensive reactions, desperate attempts at survival, recognition of key eye points, and more. Many of these can be done very quickly, though not always accurately. They still count as thinking, though. Playing quickly and playing slowly tend to emphasize different kinds of thinking, so both can be valuable.
unkx80: Actually I think for beginners, cultivation of intuition is also good. For one if one recognize the patterns, then the decision search tree can be cut down significantly.