You can make money having by having better access like the HFT firms or by having data not widely available. You can also make money by applying well known principles more intelligently than others. This latter approach usually requires a lot of money. You can't afford retail brokerage costs when you're in a highly crowded and competitive trade.

The best way to make some money as a personal trader is to take advantage of the liquidity premium in one way or another. Because you're trading money in the 5 or 6 figures rather than the 7 or 8 figures, you can take advantage of smaller opportunities without thoroughly distorting the market with your own trades. These smaller trades usually require research and market insight rather than clever algorithms. These trades are usually on financial instruments that don't have a lot of easily accessible data to build an automated trade on top of.