Poker sharks or pros are commonly described as tight and aggressive players; they don’t play many hands, but when they play, they play them like the world is their oyster.
That's a great general description, but it doesn't say much. A solid poker player is one who has mastered the four key skills of poker.
Mathematics:
A solid poker player knows the general probabilities of the game.
Good players understand the importance of outs. You ask what are outs?
Outs are simply the number of cards that will improve your hand. So
count your outs, multiply them by two, add one and that's roughly
the shot you have at hitting. A good Player can also figure out the
pots odds of winning.
Math skills are definitely the basic of becoming a poker pro, if you
don’t understand this concept you should not be playing for
real money.
Discipline:
A good poker player demands an advantage, that’s what separates
great poker players from the rest. A good poker player expects to
always win. They also understand that different games require different
disciplines. A discipline player knows when to quit playing, he also
knows he’s not perfect and will learn from mistakes and moves
on.
Psychology:
A good player is not self-centered, he empathizes with his opponents.
He tries to think the way they think and understand the decisions
they make.
Risk vs. Reward:
Pot odds and demanding an advantage fall into this category. Poker
players are willing to take a long-shot risk if the reward is high
enough, but only if the expected return is higher than the risk. You
always want to be risk-adverse with your bankroll. Have enough in
your bankroll that any given day at the tables will not adversely
affect you. If you worry about losing you will make mistakes at the
table. If you follow theses 4 skills you’ll live to fight another
day.