When a bookmaker makes a book it is done in such a way that provided bet are taken in roughly the right proportions (for the bookie) he/she will make a profit no matter what the outcome of the particular event. see link below.
Horse wise, apart from getting good information from stablehands & jockeys, I find the best way to beat the bookie is to seek out value, if a bookie prices up a horse at say 5/2 but you thing it is more of a 6/4 shot that could be value & worth backing.
Another example was the first day of the Cheltenham festival & Quevega in the mares hurdle, her true price was around 4/6-8/13 but because punters were backing other horses in the race bookies could push her out whilst still making a profit (overround) I backed her at evens & she went off 10/11, the same thing happened with Big Buck's in the World Hurdle, heaps better than anything else in the race but still available at 6/5 on the morning of the race.
Watch a few races at the weekend with the latest prices & form in front of you, see if you can spot horses where the bookies have got it wrong, this won't happen every race so keep eye out & good luck.
