He () used to say, ”When you intend doing any important work, then read two rakaats nafl salaat and thereafter read this dua.” (which is mentioned below) [Bukhari-pg. 944]
Rasulullah () once remarked to Anas () “O Anas! When you are undecided with regards to any matter, then seek counsel from your Rabb and do this seven times. Thereafter, whatever decision prevails in your heart regard it to be beneficial.” [Shaami-Vol.1, pg. 507]
Note: It is not necessary that one sees a dream or hears a voice. Asking another person to make Istikhaarah on one’s behalf is not substantiated from any hadith. To make Mashwarah (consultation) with someone else is Sunnah.