Advice for a New Pilot?

Hi all,
I've seen a lot of interesting discussion on this group
improving skills and safety, so I thought I'd ask this he I'm
currently training for my private pilot glider ticket, starting from
zero. I have about 12hrs in my logbook over 43 flights, about a third
of which are solo. I did initial training in a 2-33 and my instructor
recently checked me out in the 1-26, which I'm loving. I have a great
instructor, insofar as I'm capable of judging such things, and I'm not
worried about passing the practical, but here's the question:

Beyond reading the Knauff books and seeking continuing instruction,
what recommendations does the group have for continuing to improve
skills and be better, safer pilot after I pass the practical? I'm
almost certainly going to continue training, start learning what I
need to know to fly XC, and work on the SSA badges. I've seen what
looks like some good advice in some recent threads, and I'm certainly
looking for more. I know my CFIG is the first and best point of
contact for all these things, but I'm always in favor of getting more
information when possible. So what are the things you wish you'd
known at this point in your soaring career?

Also, I've searched for the Knauff books on Amazon, and they appear to
be out of print. Is this correct? If so, is my best bet to purchase
them through Amazon used, or are there other vendors that are
preferred?