I very rarely (almost never) use the actual Contain function, whereas I'm constantly using the Jockey button (and Sprint Jockey when appropriate, so basically the two triggers) while repositioning my defenders.
I find that this gives me finer control rather than just holding Contain and locking on, because I can define better where I want to 'force' the dribbler to go, and also control when I move in or back off.
As in real life, players will take fewer risks with the ball the nearer they are to their own goal. So if you're thinking you can wade in and tackle a centre-back or a deep midfielder in their own half, they are understandably not going to let you get close. They'll move away or shift the ball to a teammate. It's only when they get around your area, where the space is also more compressed, that they will take more risks with the ball in an attempt to make something happen. This seems logical. But it doesn't mean you can't force them backwards, harry them into a bad pass or anticipate for an interception.
Some opinions:
1. Most importantly, approach defending as a collective team exercise rather than a 1v1 drill. If you're focussing too much on the ball and not what everyone else is doing, you're going to be dissected.
2a. You need to defend by retaining your team's formation and staying organised, so use the right thumbstick to select specific players and keep your shape. Always be wary of being pulled out of position. If the dribbler cuts inside from the wing and dribbles across half the width of the pitch, pass him on to a central player rather than chasing him endlessly. Maintain your shape at all times.
2b. On that note, use the Teammate Contain
sparingly. Don't lean on it like a crutch, or your players will be pulled out of position. Use it only at a strategic moment, e.g. to help contain the dribbler while you shut off his passing options. Don't hold it for long, and don't use it without fully considering the gaps that your teammate might end up leaving.
3a. You need to defend by anticipating and blocking passing lanes. Teammates not under your control can make a reasonable effort at remaining goalside of a dribbler, so sometimes it's better for you to flick selection to a different player and move him into a potential passing lane, denying that pass (or intercepting if it is attempted). Prioritise blocking off the forward passes. The more difficult you make it for the opponent to pass forwards, the fewer chances/goals you'll concede.
3b. Similarly, if you're jockeying the dribbler, always anticipate where he might want to play the ball next. You can 'shade' him to either side, positioning your defender in a way that stops him from squeezing an expected pass beyond you down a particular side.
4. You need to defend by denying options. Thinking one step ahead. This is the key to effective pressing, and it's how Barcelona do it:
The opponent cannot play through you if he has nobody to pass to. If he has nobody to pass to, you can close in and force him either away from your goal or to lose the ball.
5. If the opponent releases a pass, don't always immediately follow the ball. Sometimes it's better to track his next movement for a moment to ensure that he doesn't just slip past to receive the one-two.
6. Know who your strong players are. When you do get close to an opponent, a strong defender can be more aggressive with the 'Push/Pull' feature and muscle them out of it.
7. If you find that attackers are skipping around you too easily... it means you're simply too close. Back off. Jockey at a distance of an extra yard or two away and you'll find that you can react to their changes of direction much more comfortably.
8. Above all, remain
patient and wait for your chance to make a successful tackle. Eventually you'll force them into a rushed/difficult pass, or you'll channel them into traffic, and then you can pounce. But only at the right time.