I used to do corporate training (MageLang Institute, which turned into jguru.com, then Tier). When I started, Java was in its infancy, and I was still coming up to speed on the language.
The trick is to know when to say "I don't know", then find out the answer and tell the students.
Students really respect this. You're not trying to BS your way through an answer, they get the answer they wanted and you learn from it as well.
On top of this, play with the language. Try new techniques and technologies that you hear about, even if you don't have to teach them.
When students ask questions, try to address them all, even if they don't relate directly to the content at hand (you may need to take some offline). Make sure you really consider their point of view; you may find your own opinions changing over time because of it.
Whatever you do, don't assume that "the answer" will always be "the answer". You may have learned something wrong, the materials the company gave you might have misinformation, and over time what was once a best practice can often become an AntiPattern.
Make sure that you spend your time learning, not just teaching, and try to stretch a little beyond the scope of the class each time you teach it. When you've learned something that adds value, or can help prevent a gotcha, or demonstrates why a certain way of doing something is a good way, make sure you show it.
One of the things that really worked for me is writing articles. I wrote several articles at my website (http://javadude.com) and participated in many newsgroups; I was the VisualAge for Java guy ;). You'll get lots of feedback on articles and posts - absorb it and learn from it, and improve the articles. [I've been a little lax on new articles, but I've got a few new ones in the pipe].
As for career path, it really depends on how well you do all of the above activities. If you get your name out there (many employers will google you) and demonstrate the knowledge you've learned, you will be incredibly marketable.
One more thing: when teaching or interviewing, think of it as "talking about something you know" rather than teaching or interviewing. It's subtle, but it makes either process much easier and more effective.
I currently teach (in addition to my day job) a design patterns class for the Johns Hopkins part-time Masters degree program. I always tell the students "everything you hear from me is my opinion; it's perfectly ok for you to have different opinions, and I'd like to hear them. Question my opinion if you don't agree! I love an active discussion because it makes sure I'm always thinking about why I think the way I do, and sometimes I change my mind because of it."
When I teach, I don't usually use slides (I might have an outline available to make sure I remember which topics to hit). I whiteboard the lecture and sit down in front of eclipse and type examples on the fly. (Note: Do not do this unless you are very confident in your coding!) I find it really raises my credibility with the students, and it can also demonstrate some of the benefits of pair programming - if I make a typo, someone in the room usually catches it before I try to run the program.
At Hopkins I record the lecture using Camtasia and post it for the students. (I use a graphics tablet for the whiteboarding so the entire lecture is captured). The students love it. I don't know if your company would go for such an idea, as they can easily be posted online, or a company could use it to train a few students and have everyone else watch the video...
Hope there's something in there that might help! Best of luck in your teaching!
-- Scott