For most students, forming the subjunctive mood is simple. It's using it that proves to be difficult. I have created this handy reference sheet that I give to my students upon completion of our subjunctive unit. They keep it in their notebook and end up referring to it often.
In the reference guide are common expressions that require the use of the subjunctive mood, divided into categories:
-desire / will
-emotions and feelings
Also included is a handy reminder that a subjunctive sentence requires two different subjects, and what to do if you're using one of the expressions with the same subject. I've also added some ATTENTION! warnings for expressions that don't require the subjunctive, but one might think they would.