The Past Perfect Tense

     We don't use the past perfect a lot in English, but it is useful, and it sounds very good if you can use it correctly. Also, it's really easy to make - just the past simple of 'have' and the past participle.

(Learn about USING the past perfect here)
The positive - make it with 'had' + the past participle (usually made by adding 'ed' to the infinitive, but a few verbs have irregular past participles):
(Also, here's some help if you are not sure how to pronounce '-ed' at the end of a verb).

I had been (I'd been)

You had gone (you'd gone)

She had met (she'd met)

He had played (he'd played)

It had rained (it'd rained)

We had bought (we'd bought)

They had studied (they'd studied)

The short form for 'had' is 'd.
(Be careful not to confuse it with 'would'. Would is followed by the infinitive - 'I'd go', whereas had is followed by the past participle - 'I'd gone').
For the negative just add 'not':

• I had not been (I hadn't been)
• You had not gone (you hadn't gone)
• She had not met (she hadn't met)
• He had not played (he hadn't played)
• It had not rained (it hadn't rained)
• We had not bought (we hadn't bought)
• They had not studied (they hadn't studied)

Here's a exercise about the positive and negative forms.
And to make a 'yes / no' question put 'had' before the subject:

Had I come?

Had you eaten?

Had she gone?

Had it rained?

Had he studied?

Had we met?

Had they left?

For 'wh' questions put the question word at the beginning:

When had I come?

Why had you eaten?

Where had she gone?

When had it rained?

Why had he studied?

How had we met?

When had they left?

Using the Past Perfect

How to MAKE the past perfect tense.

We use the past perfect tense fairly often in English.
1: A completed action before something else in the past.

When we arrived, the film had started. (= first the film started, then later we arrived)

2: To explain or give a reason for something in the past.

I'd eaten dinner so I wasn't hungry.

It had snowed in the night, so the bus didn't arrive.

3: Stative verbs only: something that started in the past and continued up to another action in the past.

When he graduated, he had been in London for six years.

(= he arrived in London six years before he graduated and lived there continuously until he graduated, or even longer)

4: As part of the third conditional.

If I had known you were ill, I would have visited you.