#2 Natural poker ability
Possessing only intelligence is not enough to succeed in poker. You may be really intelligent but if you can't learn from experience and do not have a natural affinity for the game, you are better off staying away from poker. Not only will you then save yourself from financial ruin, but you will also have the funds to invest in less risky activities like mutual funds.
With the advent of online poker, there have been a number of examples to suggest that there is no substitute for natural ability. Viktor Blom, an online poker player going by the name Isildur1, dived straight into it and won millions after learning the game through trial and error. This prodigious natural talent is also evident in other poker pros like Phil Hellmuth, Doyle Brunson and Stu Unger.