Besides the basics of being intelligent and studious... somebody who can utilize both logic and emotion. If you always play your gut, you will be awful. If you always play the statistics, you will be very good. Knowing when to deviate from the 'typical correct play' makes a player great.. imo.
In online i think very important feature is a adapt to the villains of the table, think of the range of his hands, with that in mind you will use the ideal betting size to get the maximum value of the situation.
have cold blood, control emotions, a percentage of luck and study will make you be a good player and have good chances of winning some with the poker.
Skill, luck, patience, luck, courage, luck and more luck. Software rules - ability to read bad hand of opponents is a problem in online poker if you don`t have ability to read card on river or turn.