When playing against prevent D, power-ups, bombs, and boosts are your friends. As is your offensive partner. Trying to simply knock one of them out of position enough for your partner to make a grab, or seeing an opportunity where your partner knocked them out of position enough to make a grab are good skills to learn. It doesn't have to be you to get a cap, but your team. Often times, for somewhat newer defensive players, you can 'bully' them into moving. Just keep pushing against them, and it will often cause them to want to push you away, making them leave the flag, and potentially opening the field up for a potential grab. Most experienced players know to avoid this, so not always helpful.

When fighting for buttons, if you are going to reach the button first, slow down. Allow the other players to push you back onto the button at the right time. If you are about to be pushed off of the button, brace for the impact by moving forward a bit. A sorta example of this. I was expecting the player to push more, but still worked out.

For prevent vs. return, it's more of a spectrum than either or. The best technique is to alter your play based on the conditions present. I tend to be more risky, playing return D more often, but that it not for everyone, and I am sure I have annoyed people who want to play prevent D. But it really depends on the situation. If a player I know to be a good FC is incoming, prevent D is better as it will take time to return the FC. If our flag is coming into base, prevent D can be good, but I tend to play riskier and try to force flaccids. A lot of the time it works, sometimes it doesn't. I tend not to change my play-style based on the map, though I know many others do. And if it works for them, then that is the best for them to use. Mostly just takes time learning the best situations to play one defensive style over the other.