QQQ and SPY you HAVE TO TRADE on ISLAND !!!
Otherwise, just give your money to charity, help kids in need or something at least that will do some good.
beside that, if you try to scalp these stocks you will hardly succeed. Indeed because of the spread and mostly because they are tracking stocks. So if the underlying index move, QQQ or SPY will jump directly to the new level.
If you did not anticipate that, you loose.
One way to anticipate it, is to watch very closely the futures. There are the ones moving the tracking stocks, not the index per se.
There are ways to profit in very short term with QQQ and SPY, almost [or really] scalping them. But it takes an arbitrage strategy and a lot of skill.
If you take longer moves intraday it is a little easier BUT the noise will fake you out many times [or you will use a large stop and loose even more].
Maybe what I want to say is this : you can make money daytrading the tracking stocks, many do, you have to realize that [they are usually on the other side !]. But it takes a lot of experience and you should be an advanced trader already. Beginners should stay away and trade volatile stocks [or NYSE stocks, they are underated as great daytrading possibilities]. With volatile stocks, if you can keep a small stop loss and have your winners be big enough, you can learn how to trade.
QQQ and SPY just won't leave you any place for error or learning. imo.
vpiNeo