I guess if there are ANY players here who haven't seen this YouTube video, it is REQUIRED.  Mr. Berlekamp gives a lesson on winning in Dots & Boxes, and he is, after all, THE MAN!  (elementary level - the BASICS)

(meow)

https://www.youtube.com/watch?v=KboGyIilP6k

I was just sent this link today, but I see that Purgency posted a link to the 2nd part of Berlekamp's lesson some time ago.  Oh well; here's the first part.

(meow)

Now the 4x4 variation must be shut down from this website.

Great content, Thanks @MisterCat

@KPT - is this the thread you were pointing me to?