Quote from illiquid:
For daytrading? Seriously? That's like saying if the Lakers only played Kobe for his best 5 games every season the team would have a much better record.
If your 10 best daytrades for the year net more than all your trades combined, you are in the wrong time frame.
In any case, if you even tried to limit yourself to the 10 "best", you'd probably miss out on 9 of them. My guess is I could only anticipate 1 out of 10 "home run" trades before they've panned out; the rest just happen and you take/keep advantage. This holy grail is just another fallacy involving statistics and market performance.
Daytrading, swing, doesn't matter. The best traders often say that 10% of their trades account for 90% of their net lifetime earnings. 90% of their trades are just small probes and cash flow trades. When the odds are overwhelmingly in your favor, your exposure should be 10-50x your normal bet size with a proper tier method.