Unplug the wet saw from the wall socket.
Turn the blade guard knob to the left by hand to loosen it. Remove the guard's wing nut, then take the blade guard off.
Use a wrench to remove the blade nut, then remove the blade.
Lubricate the motor shaft with spray lubricant. This will keep the blade from having to work as hard and will preserve the blade.
Hand sharpen the saw blade with a diamond file sharper, rubbing the sharpener with the direction of the blade. Rotate the blade in your hand to ensure the entire blade is sharpened.
Slip the blade back onto the saw and replace the blade nut. Re-assemble the blade guard by replacing the guard and its wing nut.