Re: faster tounging
Before you work too hard on it, make sure you are tonguing correctly first. Don't articulate with the tip of your tongue. Instead, articulate about 1/4 inch up your tongue. The motion should be up and down as if saying "tah." When tonguing normally, do not stop the air, just stop the vibrations of the reed with your tongue. Use more air to help propel your tongue.
The tongue is a muscle, you have to work it out! Practice tonguing every day WITH A METRONOME and increase the speed as you get better. Push yourself and do your best to make it as clean as possible. Try with different note lengths, too.
It has also helped me tremendously to practice tonguing without the horn. Your air will aid in tonguing, so naturally, articulating without the horn will be harder. Say "tet" with the corners of your mouth pulled back, and practice tonguing that way.
This video might help too: