I am talking about when 'were' should be used as subjunctive.
Sentences with both, when was, and when were should be used would be helpful,
The Past Subjunctive were in all persons is used in formal English:
If the minister were here, he would no doubt refute the allegations. (= formal)
However, it´s more common to use was and were in their usual ways:
I wish he wasn´t such a bighead. (= informal)
Were is more common only in the phrase if I were you, and for all persons in the pattern were + subject + infinitive:
I wouldn’t argue with her if I were you.
Were the vote to go against me, I would resign.
The subjunctive is the name of a special group of verb-forms ( eg I were, she be, he return ) which are used in a few cases to talk about events which are not certain to happen - which we hope will happen, or imagine might happen, or want to happen.
If I were rich I wouldn't work at all.
It is vital that she be warned before it is too late.
The judge recommended that he not be released for at least three years.