1. The Subjunctive following Adverbial Conjunctions
Adverb clauses modify the verb in the main clauses. They say something about how, when, where or why that action occurs, and are always introduced by a conjunction:
(indicative) conjunction (indicative or subjunctive)
Main clause adverbial clause
Siempre me siento feliz cuando me llamas
I always feel happy when you call me
The subjunctive is used in adverb clauses when the action described in the clause is anticipated or hypothetical (a reservation, a condition not yet met, a mere intention).
Voy a mandarte las fotos para que puedas mirarlas.

2. Here's a list of some of the conjunctions used :
a menos que unless always followed by the subjunctive
antes (de) que before
para que so that, in order that always followed by the subjunctive
sin que without *(but use infinitive if both clauses share the subject)
A fin de que in order that
Con tal de que as long as
En caso de que in case that
siempre que whenever, as long as
Cuando when use subjunctive for anticipated events (future)
después (de) que after
hasta que until
*Tienes que hacer la tarea antes de salir con tus amigos.