Visiting the graveyard

Sunnats and aadaab when visiting the graveyard

Q:

1. I wanted to know the etiquette and sunnah when visiting the qabrastaan? What is best for one to do when in the qabrastaan?

2. What should one recite and what will be most beneficial to read for the deceased when in the qabrastaan (closest to sunnah)?

3. When is it sunnah and most preferable to visit the qabrastaan?

4. Is there anything mentioned regarding pouring water over the qabr? If there is any book or literature on visiting the graveyard then please do let us know.