Once we're drawn off the court to either side (outside of the sidelines), it's especially tough to try to land the ball by going down-the-line and placing the ball in a small triangular patch just inside the baseline... but it sure looks cool when they do it on tv, right?
Changing the direction on that ball from out wide makes it especially tough to hit it with much accuracy - a little late sends it wide, but sending it back through the middle of the court leaves your opponent with a good look at hitting though your open court.
Answering a sharp angle with at least as much angle back across the net is often a strong option. It's usually easiest to send the ball back down the same path it came from and if your shot pulls your opponent out wide, that essentially "returns the favor". Your wide shot denies the other guy a down-the-line response the same way that his angle denies you the same shot.
Keep this option in the basic plan that you use for your match and you won't need to panic when that nasty angle happens. Revisit your plan of attack throughout your match and when those wide balls come your way, you'll already know what to do with them.
And yes, I recommend getting to the net when you can. Remember that you can make your strongest transition forward by taking your opponent's short ball and placing your approach shot deep in the far end. A deep approach can neutralize an opponent by forcing him/her to back off and hit flat-footed, but that deep ball also denies your opponent much of an angle to try for a pass.