Use the subjunctive after these phrases/conjunctions, only if a dependent clause follows them (I was happy *that you took French*, J'étais heureuse que *t'aies pris le français*) and the subjects aren't the same** (if they are, use an infinitive: J'étais heureuse de prendre le français, I was happy to take French).
**Unless you're using conjunctions like pourvu que, bien que, quoique, non que, or jusqu'à ce que
Use the subjunctive with: wishes, complex commands (Evitez qu'il ne parte, keep him from leaving), emotion, some impersonal expressions, requests, doubt, questions of certainty, certain conjunctions, sometimes with superlatives, indefinite expressions, and relative clauses indicating the uncertain existence of wishes (I'm looking for a man who is rich, je cherche un homme qui est riche). You can also use the subjunctive by itself (Vive la France !) to express a general wish or command.