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.
When first starting out you should be buying all the books you can read on the aspects of gambling that interest you. The gamblers Book Club in Las Vegas is a great place to start. The internet now offers more opportunity for learning than anything I've ever seen in my life. Gambling conferences are a great place to cut your teeth lso. I personally don't attend these functions for personal reasons not because I don't think they are helpful. Las Vegas used to be the Mecca for most professional gamblers but with the internet and opportunities in other locals this is no longer as true but still a reasonable place to make new contacts and a place to hone ones skills.
Expect both positive and negative flux in your bankroll. If you decide to be a professional blackjack player you will at some point lose 60 top bets during your career. If you play long enough you will have a losing year. If sports are your choice, expect to go -22 on a busy college Saturday at some point. If you never seem to flux up or down you are doing something wrong. If your emotions annot take flux you need to pick a different profession. If you enjoy flux this could be a bad sign also. When your bankroll fluxes upwards this is not the time to buy that fancy car you have always dreamed about. There will be plenty of time for all of that but until you have a substantial bankroll (at least 500K) you will need to preserve capital. Things can go bad in a hurry in this business and you need to be prepared to weather the storms.
Expect to put a huge time investment into gambling. It is not uncommon to put 80+ hours/week. To be successful this is a business that will take over all aspects of your life. Once you get established and secure with yourself than you can cut back on the time investment but many guys still choose not to.
If you have the ability to make more money doing something else you probably should stick to something else. This business can be an emotional roller coaster and the only thing (in the long run) to justify it is the extra money.
Realities of the Business
You have no bosses or customers to speak of so you are totally independent of the bull shit most people go thru in a normal day. This is the good part. The only person that you need to answer to is yourself. Don't bullshit yourself or you will become a bad boss. Be true to yourself.
You produce no product or service that society requires. This is the bad part. As you become more successful your purpose in life becomes more meaningless. While other guys are saving lives, producing goods and services you are not much better than a parasite to society. With success comes (a feeling of) a debt you owe to your fellow man. Most successful gamblers I know give heavily to charity; donate their time and money to help their fellow man in some small way. I believe it is their way to make up for the empty feeling one gets from years and years of not producing something of substance. Many successful gamblers look for something else to do with their lives after becoming financially independent. Relationships don't work for most of us early on in our career so this is another avenue many professionals look to achieve as they become financially successful.
Source: Financial Spread Betting