Good article written back in 2008 by Simon Rowlands who blogs on Betting.betfair.com website,well worth read if you are interested in gambling wisdom .
1) Value - the number one rule. Back enough selections at odds bigger than are merited by their chances and you have cracked it. Most other rules are ways of bringing this to pass or of ensuring that you capitalise on this advantage. Value can involve backing something at 1.1when it should be at 1.01 or at 40.0 when it should be 20.0, or of laying the bets to others when the opposite applies. The problem in betting on horseracing and other sports is that it is not possible to know for sure what represents value in an individual instance, as would be the case with cards or coin tosses. Nonetheless, value as a concept is an inescapable truth. Betting is, in effect, an extended experiment in determining how good you are at judging value.
2) Take responsibility - if something goes wrong with your bet, do not automatically blame the jockey (who you knew would be riding your selection), the tipster you followed or the statistics you used (in both cases, it was your choice). Most of the best punters I have known have considered whether they have made a mistake with their bet - even when it has won - and sought to learn from the experience. They have taken responsibility for their actions, in other words. Bad punters almost always do not.
3) Fear and greed - thanks go to Andrew Black, founder of Betfair and one-time professional punter, for this gem of wisdom. As "Bert" once said, good punters have the right balance between fear and greed. Most bad punters are too greedy, trying to win too much at one go or increasing their stakes the moment they become successful (or greedily chasing their losses when they are not). Then again, I am too cautious by half. I frequently have not pressed what advantage I do have and am forever looking gift horses in the mouth. Try to find the balance appropriate to the type of betting you are engaged in.
4) Discipline - do not give in to the temptation to bet on more events than is suitable given your knowledge and preparation. Remember that you have the power not to bet at all. Do not chase your losses or get carried away with your wins. If in doubt, get up, walk away and come back another day. Similarly, do not cut corners in your preparation - betting tends to punish those that do - and discipline yourself to bet only when you are in a position to do it well.
5) Adapt or die - even in the eight or so years that Betfair has been in existence, things have changed markedly. More sophisticated forms of analysis are available and where the edges are have changed greatly. I started off laying books, primarily in the place market, moved on to the win market, did a bit of in-running betting before it became quite so popular, spent some time (when I was busier with other things) betting on individual race winning-distance markets in their infancy and have reverted to fairly old-fashioned on-the-nose backing (and laying) in recent times. Betfair provides the punter with huge choice and flexibility. It is my experience that, on Betfair at least, when one door closes another usually opens. Do not get stuck behind a closed door.
6) Play to your strengths - while point five urges the need to be versatile and adaptable, you should never bite off more than you can chew and should always play to your strengths. My knowledge of horseracing has been built up over decades, whereas my knowledge of Big Brother is short-term and superficial. It does not prevent me from betting on the latter, but I am well advised to know my limitations in this area. By a similar token, I feel comfortable with numerical analysis of horseracing - ratings, sectionals and the like - but far less so with paddock inspection, for instance. Paddock inspection is important, but I do not immediately leap on something that catches my eye before a race when others are better placed to do this.
7) Staking and money management - the Kelly Criterion is, to the best of my knowledge, the last word in correct staking. Even if you do not act on every last symbol of the Kelly formula (I do not), be guided by the basic principles: you should stake a proportion of your bank in accordance with both the edge you perceive you have and the likelihood of the event happening. More generally, bad punters tend to vary their stakes alarmingly, ramping them up markedly the moment they get a few winners (or, in some cases, a few losers). Set aside money for betting and manage it so that you are in a position to capitalise on opportunities when they arise. Be consistent: play the long game.
8) Pace yourself - if you are betting at all seriously make sure you find time for other things, and do not become so obsessed with turning a buck that you burn yourself out. I used to give myself incentives and rewards for good behaviour and good results when I was betting for a living. I operated better if I had some "down time" a few times each week, and I made sure I took holidays. I imagine something similar applies to everyone.
9) Question received wisdoms - betting, and in particular horseracing, is full of received wisdoms. Some of them stand closer inspection (the primacy of "value" is a good example) but many do not. It is a human trait, encouraged by evolution, to look for patterns, and it is a human weakness, punished by experience, to see patterns where they do not exist. Pace biases, draw biases, track biases, golden highways, yardstick handicapping, trends, favourite jockeys, five-year-olds in the Champion Hurdle, going preferences of the offspring of sires: some good has been spoken and written about each of these but even more balderdash and piffle. Be sceptical, without closing your mind. There is a lot of mileage in going against the crowd.
10) There are few golden rules - betting on racing has had an enduring appeal in no small part because it is pitched at just the right level of complexity for the human mind. It has a habit of punishing the grimly deterministic and the fickle backer of hunches alike. Remain flexible: use judgement and intuition where it is appropriate.