Try to get as much experience in different environments as you can. By the time I began my instructor course I'd been in fresh and saltwater, cold, low vis, current, caverns, wrecks, kelp, and nice easy stuff. While doing it I tried to dive as many different gear configurations as I could. Some worked well while others not so much. But the idea is that I could dive them all at any time. I'm looking to do some sidemount stuff this year if possible as well as vintage.
I see instructors who week after week are in the same gear regardless of conditions. Nothing wrong with that except when their students ask them questions about what I am using and they truly cannot answer them. As an instructor you should at least be familar with any configuration enough to intelligently answer why that may or may not be the best choice for your students. By the time you make instructor I feel you should be able to take any BC, of any size that you can get on and in few minutes be able to figure the weighting out, get neutral, and get in trim.
Once you become an instructor plan on continuing to learn new things. I took an Ice Class and am planning on more training in different disciplines from those I respect in them. Also keep your eyes open for things you would not want your students to see in an OW class. Plan on teaching your class so that your students are not swimming single file with no buddy, that they are not tearing up the bottom, and they are self sufficient. You really can only do that by becoming that type of diver yourself. Work on skills every dive at some point. Even if it's just holding trim and depth with no more than a variation of 2 feet for 10 minutes while swimming. Then do skills while maintaining it. Mask R&R, reg R&R, weight remove and replace, etc.
And as the others have said - Don't rush it!