It is a nice easy skill to get the hang of. But you would benefit from lots of experience to learn the sets usually used by the Pokemon you will commonly face. Let me give you a situation.
You
Abomasnow, Raikou, Magmotar
Opponent
Scizor, Heatran, Suicune
So lets say you lead with Aboma and he leads with Sciz. Your going to want to switch. He could be predicting that but for now he does not make predictions. So you have now the advantage. But he will not want to stay in. So you can predict his most beneficial switch and go for Thunderbolt or Focus Blast to hit who ever switches in. Alternatively lets add Milotic to your team. Obviously you can't add random Pokemon in a battle but for now :D. So Heatran and Suicune can't even touch Milotic and Milotic can stall them out so you can pull a double switch as they switch which gains both momentum and makes for an interesting game. So once again you have he advantage.
Anyway the example was crap, yes I know. But imagine your playing a decent battler. You have to predict what they are predicting. Play out every single possible scenario in your head. Because if your switching they might predict that. Also don't be to obvious. By this I mean don't always go for the obvious plays and mix it up a bit. If the opponent thinks your gonna pull off a double switch maybe don't.
Now this article is ancient so I will find an updated one but it still applies and yes do sign up for the tutor and apprentice system. If there is anything you are unsure about in my answer please comment ans sorry if this all seems quite basis :D
