In a very passive 10 player game with little to no preflop betting, and flop gives me top pair top kicker along with 2 same suited cards, how should I bet against the very likely flush draw?

Should I wait until after the turn card to bet ( to minimize chances of a flush ) or should I just raise immediately at the flop? Or should I make different sized bets at each interval?

There's also a risk of someone getting 2 pair or a set, but I'm playing against other newbies who usually make it quite obvious when they get such a hand.