Without a plan in the system:
"You" Tamworth Tower this is Aviater Bravo Charlie, flight details outside the zone
"Tower" Aviater Bravo Charlie go ahead details
"You" Aviater Bravo Charlie for Brisbane direct, request taxi clearance received ATIS
"Tower" Aviater Bravo Charlie clear taxi holding point xxx runway xxx
"You" Clear taxi holding point xxx runway xxx, Aviater Bravo Charlie
"You (somewhere along the taxiway)" Aviater Bravo Charlie request airways clearance
"Tower" Aviater Bravo Charlie airways clearance is depart on track to Brisbane climb not above 3500 (or whatever)
blah blah blah
Just start and go, works for me every single time. Good confident radio = easy clearance BUT take what clearance you get given. Be prepared to track outbound via somewhere (not likely at Tamworth). Have the VTC on your knee. Fly visually.
In plain English, start and go, wing it, have fun. You only need to get OCTA which is pretty close by.
With a plan in the system:
Aviater Bravo Charlie for Brisbane, request taxi clearance received ATIS
Etc etc etc. A plan may make it a tad easier on the radio but VFR you are at the bottom of the pecking order and will still get what your given. Struth, at Tamworth heading north, OCTA is only about 5 miles away if you can dodge a few hills, and only 15 miles away if you want a little more height. Its pretty well a given that you will be cleared in this direction.
Me: A plan? Never. This has never caused a problem with clearances either. Remember, good confident radio will get you most things you want when you want them if your intent is OCTA asap.