Once you see that the toilet is draining slowly or is stopped up, do not flush it again. It's time to use the flange plunger. Gently push the plunger through the water allowing air to escape from the plunger body. Once the plunger is sealed around the drain outlet in the bottom of the bowl, plunge up and down rapidly until the clog is broken and the water level seems to drop.
Next, you have to test to see if the toilet will drain.