I'll give you a super-simple explaination for using the subjuctive, so you can start using it. Remember this is way over-simplified.
Let's look at an example.
"I want to go to the store" - "Quiero ir a la tienda"
"I want" is conjugated and "to go" is in the infinitive, just like in Spanish. Now let's get two people involved in going to the store.
"I want
you to go to the store" - "Quiero que vayas a la tienda"
Since there's two people involved (I'm doing the wanting and you're supposed to go to the store), we need to switch to the subjunctive and conjugate that infinitive.
So here's your homework (you thought you'd get away without homework did you?):
Take these two patterns in English:
I want you to do something
I hope you do something
and whenever you go to say something in English that fits these patterns, for instance:
I want her to come to the club tonight or
I hope he doesn't crash,
try to say it in spanish. Even if you don't know all the vocabulary, practice the structure, which would be:
Yo quiero que ella venga ...
Yo espero que el no "crash in subjunctive" (choque).
Another way to practice is instead of thinking
"I hope she comes" think "I hope that she come"
"I hope he doesn't crash => "I hope that he not crash"
I hope that helps you

(Espero que eso te ayud
e)