Okay, I'll just comment on "technical" things. You definitely sound like you have dry mouth. Using some lemon juice diluted with water as a mouthwash - and yes, gargle with it - does a great job of getting rid of phlegm. You should also cut down on dairy products. If you have chronic dry mouth something like Biotene does a nice job.
You really need to work on your diction, you sometimes mumble. I run into this problem with singers all the time. When you initially start working your lines you should over-annunciate everything. Really exaggerate your lip and tongue movements. Make sure that you very firmly and precisely hit all of your consonants, especially word endings. When you have it all memorized and are ready to begin working on the emotional content you will naturally relax the over-emphasis and are (hopefully) left with clear speech.
Just for fun you should try tongue twisters - I had a singing coach who insisted on them. You feel really stupid at first, but after a while it becomes a fun party trick, especially if you can pull them off after a few drinks. Here's a few...
Try saying "Toy Boat" five times without screwing up.
Single line tongue twisters must be repeated three times:
"The Big Black Bug Bled Black Blood."
"Red Rubber Baby Buggy Bumpers."
"Sheena leads, Sheila needs."
"The sixth sick sheikh’s sixth sheep’s sick."
This one is supposedly impossible to say - it was devised at MIT.
"Those seven silver snakes should step to the side."
A few classics:
"Peter Piper picked a peck of pickled peppers
A peck of pickled peppers Peter Piper picked.
If Peter Piper picked a peck of pickled peppers,
Where's the peck of pickled peppers Peter Piper picked?"
"How much wood would a woodchuck chuck
If a woodchuck could chuck wood?
He would chuck, he would, as much as he could,
And chuck as much wood as a woodchuck would
If a woodchuck could chuck wood."
"I slit a sheet, a sheet I slit.
And on a slitted sheet I sit.
I slit a sheet, a sheet I slit.
The sheet I slit, that sheet was it."