I can't find it now and I don't really feel like looking too hard, but a paper I read linked at CXO Advisory's website analyzing retail traders' profitability showed that of the ones who were profitable, they primarily fell into two groups: traders who made 1-5 trades per day and traders who made 750+ trades per day. So, if you're going to try to be a successful trader, try to develop a strategy which puts you in one of these two buckets.
Of course, the frequency of trades is only one variable in a long list of variables, but it seems to indicate that if your strategy doesn't put you in one of these two groups, you face longer odds. I think it makes sense because the trader trading 1-5 times is probably working with one or a couple of markets and set-ups and gets to know them well and the trader trading over 750 times/day is really almost like a small hedge fund and presumably has grown from trading a few times a day to scaling the methodology up to current levels.