DislikedI haven't tested this but I would suggest one very simple filter to increase probability. Only buy when the daily bar is above it's open and only sell when it is below. That's it. Sounds too simple but usually the simpler ideas are the best. Daily should start at 6:00GMT which is the start of London. You can eliminate this time variable from your broker by looking at hourly and determining exactly which bar is the start of London market. That will give you daily opening price based on 6:00GMT.
This method works with a lot of other systems and...Ignored
Excellent point pip daddy..i use this as filter for other trading methods as well.