pro gambler

Qualifications
Discipline: If you have to make a bet for the sake of making a bet you are in trouble.
Focus: If you are distracted with other activities, people, family or problems you will not be able to give gambling the attention it requires.
No Superstitions: I personally do not know anyone who is superstitious and successful at the same time.
Record Keeping: Show me someone who does not keep records and I will show you a loser.
Ego: I've seen this be the downfall of what otherwise may have been a good professional gambler. Until you have won 10 million or more gambling, check the ego at the door. If you have reached this level of success than why the need for the ego.
Emotions: This one is key. You must not let the highs and lows affect you. If you cannot do this than you need to find another profession. Examples of the bullshit I've heard ten thousand times. The ref made a bad call. The stupid jockey judged the pace wrong. Some dumb ass took MY card. Why did or didn't they go for the 2 point conversion. If you are or want to be a professional gambler this is going to happen everyday, SO FORGET ABOUT IT. If you can't handle it you have almost zero chance of success.
Pull the Trigger: When you have the advantage you must be able to make the appropriate bet. If you look at money in terms of what it could buy you, you're in the wrong business.
Bankroll: First you need to have one. What you can borrow on your visa card does not count.
Bankroll or Money Management: There are some good books on this subject. If you do not know what I mean by money management you need to buy such book. Hint: You cannot play 50-100 stud on a $10,000 bankroll. You cannot bet $5000/game on a $50,000 bankroll. You cannot play a $5 video poker machine on a $100,000 bankroll. If you try this you are not a professional gambler you are just a gambler who will go broke sooner rather than later.
Maths: This will win you more money than any other single factor. If you don't know the math than you better learn it or at least know someone who will do the math for you. If you don't like math than find another occupation.
Adversity: As in any endeavor there comes adversity. Be emotionally ready to handle it because it is a sure thing. You will be barred from casinos, cheated and stiffed during your career, that I can promise you.
Be true to yourself: Resist the temptation to do things that are detrimental to your well-being and your bankroll. Going on tilt, drug use, and binges will have a negative affect on your ability to perform. Even a bad diet will have a negative affect. Whatever form of gambling one embraces it always gets down to who's brain is functioning the best, who has the bankroll, who knows the math.
Reputation: To me this is everything. Without a good reputation you will never be a professional gambler in my eyes. You may win money, but doing it without honesty and integrity you're just a bum to me. If you win by cheating, scamming or stiffing people you're not a professional, you're a cheat, scam artist or stiff. A good reputation will become your greatest ally in the war to win. Once you establish a good reputation opportunities are everywhere. Other professionals welcome the chance to work with you, help you, and partner up with you. Having a good reputation does not mean keeping your word 9 out of 10 times, it means 100% of the time keeping your word. I know a professional poker player in Las Vegas who did not do the right thing 25 years ago and to this day nobody will have anything to do with him. Once you sell your reputation you can never buy it back.
To be a professional it takes a rare mix of qualities not found in most people. As one well known professional poker player likes to say "Its a hard way to make an easy living". To be a professional at anything it takes a unique person and gambling is no exception