Activate Krenko by tapping it, creating at least four 1/1 Goblin creature tokens.
Activate Phyrexian Altar four times by sacrificing four Goblins, adding ({4} magic symbol) .
Activate Staff of Domination's third ability by paying ({3} magic symbol) and tapping it, untapping Krenko.
Activate Staff of Domination's first ability by paying ({1} magic symbol) , untapping it.
Repeat.
If you control five or more Goblins as this combo begins, you may get infinite mana, which you may use to activate Staff of Domination's other abilities.