Bear in mind that this course is a long-term commitment, and you will be studying these techniques for many years to come. Your gains will not be overnight.
That said, be aware that all vowel sounds in the English language stem from the AH vowel. Don't get too attached to the "L" consonant of LAH! Pay more attention to the Open Throat AH that follows the "L". So let that AH be a freely flowing fountain of sound. Like a Fire Extinguisher, pouring forth your vowels, and minimize your consonants so that the vowels keep flowing with minimum interruption of the Open Throat.
Brighten it up as much as you can. This will give you a more contemporary, modern sound as opposed to an Operatic sound. Remember your support is the source of your vocal strength! Proper breathing along with support from all chest and abdominal structures. Your Body is the instrument, not just your throat and mouth! Without massive support you will be singing from the throat. Sing from your body!
Good luck on your upcoming performances, er, I mean Break a Leg!!!