I can give some advice, but you should take it with a grain of salt :) I have been more of an infrastructure guy, and building the platforms with quants/traders, and not really trading myself. I am also more familiar with HFT trades overall.

I think you're on the right track regarding value investment, if you're thinking about it long-term, and it's for personal investments. Passive index funds like SPY are the best bet for most people. Finding companies or following trends you in particular have some insight on can also help. Things like "having worked in industry X, and having read their whitepapers, this new company is clearly overbought and is all marketing hype".

If you want to get more analytical, look at portfolio theory, different hedging strategies, and try and find "alpha" - roughly meaning the extra factors explaining the price of an instrument that gives you an edge over others. Check out Quantopian - they have some nice articles too. The key is coming up with a model that accurately captures the risk of your assets which would allow you to properly allocate your money amongst them.