Wait for a dozen to repeat, once it repeats then bet all other numbers on the board not part of the dozen
for example
32 shows up and then 36 shows up
now bet all the numbers on the table that are not in the 3rd dozen
wait for the dozen to repeat twice in a row
good results so far flat betting
Just lucky.
I have done better with waiting for a dozen to repeat and then playing the two numbers that triggered the attack for 6-8 spins. Fibo like progression modified to the play then down 2 stages after a win and play for three wins total on an attack before resetting to one unit. A repeat of a single number does not trigger an attack. If another dozen repeats within the attack...play them both out.
It's not a play for everyone.