On the other hand, the turn card may have helped someone. If someone who was kind of passive so far, suddenly springs to action now, be careful. You may have been outdrawn.
If you have played the flop aggressively because you thought you had the winning hand and the turn card was not too scary, keep betting (continuation bet). Try to make calling as expensive as possible while you are ahead, do not give free cards with hands that are vulnerable.
To demonstrate strength, there is one trick you can use online: Check the “bet” box before it’s your turn. Your bet will then seem to be coming very quickly and without hesitation. That will induce a fold rather often. If somebody else bets before you, no problem: the software will offer you the remaining choices.
If your hand is so strong that you want the opponents to call, you can take your time and then bet – but do not forget what we said about slowplaying your hand! Sometimes, of course the other guy will see through these manoeuvers, but he will still be uncertain about your holdings.
Never forget to think about what the others might be holding: the turn card may have helped you, but it may have improved the other guy’s hand even more sometimes!