Firstly, before I say anything else, trading is gambling and can go wrong. DON'T risk more than you can afford to lose and NEVER chase your losses.
Trading Tennis can be profitable because the odds are very fluid and trades can be done in minutes. In order to make a profit you need to find a game that satisfies certain criteria. Firstly, I only ever trade on mens singles Tennis matches. The reason fo this is that the mens game is far more predictable with less breaks of serve. Secondly I never trade red hot favourites. There's very little room for manouvere if the players price is 1.1 or lower at the start. Find a match where the favourite is between 1.4 & 1.6, it helps here if you know a bit about Tennis i.e. current form or preferred surfaces etc. For instance a player may be favourite on reputation but may have lost his last 3 matches to his opponent on that surface, not a good bet.
You can trade a match right from the outset but I like to wait until both players have played a service game. If your man is going to get broken then his first service game is the most likely. The best time to place your back bet is at the start of your players service game or right at the end of the other players. This is when the price is likely to be highest. If your player holds serve then his odds will drop and before the next game you lay off for equal profit. This can be repeated right through the match, building your trading profit. If the player you are backing has his service game broken then his odds will go out leaving you in a poor trading position. Best practice here is to trade out for a guaranteed loss, rather than lose your entire stake.
"All you need to ask yourself is do you feel lucky? Well do you......Punk!"