I would watch the Paul Tudor Jones documentary, "Trader." It's available on Youtube. There's a segment where he trades crude oil ahead of an OPEC meeting.
The reason you are making noob mistakes is because you don't know the triggers of the pros. If you did know them you would be entering and exiting at market turns. Concern yourself with learning the pros's triggers and forget about noob mistakes. They will go away once you know what you are doing.
I second forward testing. The algorithms of the pros move the markets so forward testing will show whether your algorithm is in sync with the pros. If it's not, then move on to a new trading rule.
I use ExcelPriceFeed which brings back the opening price, closing price, high and low for every stock I enter into Excel. Then I use proprietary price action analysis to choose stocks.