You speak like you have experience in the witness game Nainaz.
To get the votes of the big guys you usually first have to talk with them, they are very picky with whom they give their votes to because many witnesses ask them.
Gotta build an army of Minnow, Dolphin and Orcas, losing their vote doesn't hurt as much compared to losing a whale vote so it is better to get as much of their votes as possible.