I am a French teacher and I didn't know there even was a subjunctive in ENglish : my students learn English without it.
The question is : what is it? Are you sure you need it?
Let's try the French approach : it's called the notion-function approach (sort of) and we try to trigger speech. therefore we wonder first what the use is : what will they need to express that requires the subjunctive? Then, we give them an assignment :a dialogue to write with a precise situation to write about, which requires the use of the tense.
For example, I teach the "modal preterit" introducing it by triggering their need to use regrets and hopes, and I get "I wish, If only, I'd rather, it was time" sentences and I give them the rule to apply.
Does it help?