The biggest change to your workflow will be due to the integration of Plotmaker (as of AC10). I recommend checking out whatever you can find about the migration from 9 to 10. You will want to revisit your file and document organization standards. The details will depend on your practice.
A couple of big improvements in modeling are the complex profiles and curtain wall tools. Learn about the profiles as soon as you can. They are hugely useful. You can learn the curtain wall tool as your projects require.
Oh... and the Solid Element Operations are very much improved. The results still don't show in plan
but they are very robust now. I use them foer all sorts of crazy things and I can't remember the last time they broke.
Teamwork 2 is the big change to come with AC13. This is a huge improvement (which is advanced further in AC14). If you have a need to share projects you will want to get into this as soon as possible.
Of course there are lots of other improvements which may or may not matter to you. I recommend that you get hold of the new features guides for each of the intervening upgrades just to get a quick idea of what all the changes have been and pick out the ones that matter most to you.