I've been working on a comprehensive guide to team building and a summary graphic that covers general concepts, key things you'll want to consider, and multiple approaches to team building for both GO Battle League and declare-6 formats. Check out the full article here on PvPoke.com. Hopefully, it helps both those new to team building and seasoned battlers alike. Also, I'm getting some help translating the graphic to Spanish as well, which should be coming soon.