I also do daytrading, so cannot say anything for swingtrades.
A daytrader can only surive (and in a good case make money), by trading "thin stocks". If you trade "thick stocks" (MSFT, CSCO) you're just having a nice time, but not making money in the long run, or veeerrrrryyy slllooooowwwly.
How to define "thin" stocks? Well, I would say, the best would be MSFT"s for tomorrow. But how to find them?
-They should have enough liquidity to be able to shuffle around 2000-5000 lots easy. So for me I keep around 3mln daily as a minimum.
-Not less than 5$
-Good volatility and high ATR.
-ANd in contradiction with the above, a low spread.
That's where the tradeoff comes. And finally, it depends on how much risk you can/will take, which is closely related to your account size.
TFD