I find it interesting that Steve T. trades this way, because i would describe myself as also trading this way. Steve T. as many of you know is the most consistant trader probably on this board. I average about 1 negative day every 25 sessions, and that is normally quite good, but he averages 1 negative day probably ever 40-50 sessions.
I agree with the OP that you can feel a stock is going to break up/down at least for the immediate short term. The problem i have found is that the liquidity available at these profitable entries (and often exits) is generally fairly thin. I trade in 900/1800 share lots on a stock that does around 4million share a day. I scalp out around 18-100 bucks on a good trade, and lose 0-50 on a bad trade, occasionally more (sometimes you just cant help getting fooled). I made about 100 round trips a day.
The key in my opinion for enhanced profitability with this type of trading is to know when you can take a swing and take more shares than your default. For instance a situation generally arises a couple times a day when i could take 5-10k shares with similar risk than 1800. It is these special situations that extremely quick decisions are needed to profit. Sometimes hindsight is the only way to identify them.
I trade off of 1 minute charts, no volume or indicators, but i do somewhat 'predict' the movement based on prices relative position.