[andersamundson]

Read Ed Thorp's 'A Man for All Markets'. Fantastic biography of an extraordinary mind. Godfather of stat arb/market neutral.

It is also very helpful to understand how corporate finance works. Read 10-Ks from a few company you're interested in. These can be found on the company's investor relations page or in the Edgar database. (Ideally a consumer driven company that makes stuff for people vs a bank, energy co, etc). Learn how the various financial statements interact. While you're looking at this study DCF valuation.

Get an idea of how non-quants evaluate investments. Particularly good are Howard Mark's Chairman's Letters and David Einhorn's 'Fooling Some of the People'.

Read Taleb's 'Fooled by Randomness.'

Read more Taleb.

Completely ignore financial media (eg CNBC).