what am i doing wrong when i clean laptop fan?

power off and unplug first, and let it cool if you've just been gaming on it. if it's still loud after a proper clean, the dust wasn't the problem - check task manager for something sitting at high cpu. on an older laptop the thermal paste dries out, and repasting makes more difference than any amount of blowing.

hold the fan still with a cocktail stick while you blow it, otherwise the air spins it far faster than it's designed for and that can kill the bearing. short bursts, and aim from the exhaust vent so the dust comes back out the way it went in. is it running hot or just loud?