If you want one thing to act on, pick the race before you pick the horse. What the bookmakers charge varies far more from race to race than anything you can turn up by studying the horses inside a single one.
That is the short answer, and it is worth being plain about why it is the answer. Our own testing keeps finding that backing favourites loses, that form study does not beat the market, that staking plans do not help and that accumulators make it worse. At which point the reasonable reply is: fine, so what am I supposed to do on Saturday?
The honest answer has two halves. The first is that we cannot tell you which horse will win, and neither can anyone else who is being straight with you. The second is that quite a lot of what determines your afternoon has nothing to do with which horse you pick, and that part we can help with.

