All you need is an IDEA.
I have been operating largely according to principles of value investing, while occasionally I deviated and tried to catch short-term momentums (which to me are more like anomalies). However, this is also where I learned lessons from my deviations: once you formulated your own principles, never deviate from them.
I have found many occasions that when I deviate, I would generally be wrong and suffer undesired losses.
Reality has taught me that you cannot outperform any computer algorithm in trading in short term, since machines are so much quicker and more precise in computing and capturing moments than human brain, not to comment on human emotions and subconscious decision-making mechanisms. However, if you stick to your principles in the long term, it is absolutely possible to outperform those machines, since they are simply digesting data that are generated by human actions and spitting out whatever optimal solutions they deem fit, again based on these human trading data.
In a word, garbage in, garbage out. After all, it is those humans that formulate those algorithms for the super computers, and indeed, since they are man made, they are still prone to errors.
Conclusion: don't try to play short-term tricks with computers, outsmart them in long term with strict and well-formulated principles.