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True, that is why most people are using bot to ease their trading. Doing trade manually will only get yourself burnt especially if you are doing it in a high volume market where the margin of buy and sell are almost none and not to mention that human's speed is limited, price may shoot up immediately without you knowing , i.e few weeks back someone mistyped a zero on btc-e and executed a 10k BTC buy, shooting the price straightforward.
Another options will be trading in a non fee exchanger , most chinnese exchanger applied a zero fee market though.
I was simulatiing some bot trading, but even that didn't go fully according to maths.Even if my bot tries to sell some coins, the pure fact of selling creates a downwards shift in prices.
@ News' influence on BTC price: What I see is that it has a temporary effect

Slight variation because of people thinking what it will bring, then it goes up/down (back) where it (roughly) was. Of course major news have different impact.