I can't answer for Terry, but want to add my ideas. For me, the most important thing is "Do you enjoy this?" If you're having a great time, that's the #1 thing.
Taking it from there, it's all about finding your passion and doing it when you're ready. A few things to do to get ready:
1) Take a stand up comedy class. Even if you're not going to be working in stand up comedy, the things you learn will carry over into so many other areas of performing. This is especially true of learning how to build your set and learning how to say things in the right order so it comes out and delivers more laughs. (Sometimes, simply changing the order of the words makes a joke 100% better).
2) Get into a regular routine. Focus on specific things during that time. Plan to work on writing one practice session, puppet control the next, and lip control the next session. I found it easier to concentrate on one thing at a time in the beginning.
3) Spend time talking to your puppet. Not in a psychotic, thriller movie, sort of way by taking it out to the park and sitting with it....make sure you do it at home. Just get a feel for the personality you're trying to portray with the puppet. You'll eventually find your puppet saying things that surprise you.
4) Don't use someone else's jokes or routines unless you have their permission. This is a big mistake beginning ventriloquists make. I made it early on and wish I never did.
5) Write every day for at least 15 minutes. It doesn't matter if you sit down and start writing, "I don't know what to write. Today was boring. Nothing happened." Just keep free writing....something will come up.
6) Buy a lot of Axtell puppets (I am just saying that to win brownie points from Steve).