Stephen Page wrote:
What's the best to read up some more?

I really like Jobson's 'Championship Sailing'. But I'd also say that you
can spend too much time reading and not enough time on the water practicing.

Also is tacking on a wind shift the thing I need to get nailed down
first and foremost?

I wouldn't worry about the shifts and just work on the fundamentals of
tacking. Hitting the shift just right is nice, but not losing several
boatlengths in a tack is a lot nicer. It's really all about maintaining
and maximizing boat speed. (I'll also happily argue with whoever said
that not tacking is guaranteed to be faster than tacking. Lots of boats
can gain with a good roll tack; 42.2.e is there for a reason.)