My strategies are:
1. Bet on heavy favourites in the beginning of the week (when the odds are biggest for them) and minutes before the match starts I place an opposite bet on another bookie. It is almost sure that the odds for the favourite will have droped, because many of the punters in the world are betting on them.
2. In leagues where under (2.5 goals) matches are very common (France 1 and 2, England Championship, and others) I'm betting on under and then I'm looking for Live In-Play markets where I can sell this under bets at the half-time for example.
3. I'm making personal estimations for tennis matches and where I like the big underdog I'm backing him/her with small stake and again on Live In-Play I'm selling his odds when he tightens the match or is leading with set, games, and so on.