The Sideline is your strongest Defender.
Getting turnovers in the attacking half of the pitch is one of those things that can really change a match, as the defence is often out of position, and big scores can come of these turnovers.
The coach will often shout things like "Push Up, and "Tackle"....trying to get their players to get another hand in that will ultimately lead to a turnover.
Against good players, a turnover in the attacking half is a very hard thing to achieve, especially if the opposition players are comfortable off both sides, and are composed on the ball.
To improve your teams chances of getting a turnover, the defending team should try and push the team in possession towards the side line, and then push up and tackle.
No matter how strong or powerful the player in possession is, the cannot run through the sideline, and must turn back.
This will present turnover opportunities, if everybody is tuned in.