There is always space for improvement, no matter how long you've been in the business.
Every time a football player goes to ply his trade he's got to play from the ground up -- from the soles of his feet right up to his head. Every inch of him has to play. Some guys play with their heads. That's OK You've got to be smart to be number one in any business. But more importantly, you've got to play with your heart, with every fiber of your body. If you're lucky enough to find a guy with a lot of head and a lot of heart, he's never going to come off the field second.
Avoid stock expressions (like the plague, as William Safire used to say) and repetitions. Don't say that as a boy your grandmother used to read to you, unless at that stage of her life she really was a boy, in which case you have probably thrown away a better intro. If something is worth hearing or listening to, it's very probably worth reading. So, this above all: Find your own voice.