Advice for attending a playtesting event: before, during, and afterward:

https://mailchi.mp/2f2e3fcc0d5d/suyg4

“Be an artist, not a scientist. Avoid any fixed methodology, and don’t follow well trampled paths.”

— Reiner Knizia

What to ask players in a post-test questionnaire--a BoardGameGeek designers forum discussion:

https://boardgamegeek.com/thread/1975599/post-play-questionnaire

The right and wrong ways of including examples in rulebooks:

https://hollandspiele.com/blogs/hollandazed-thoughts-ideas-and-miscellany/e-g

The causes of analysis paralysis, and ways of addressing them:

https://www.tricorngames.com/designer-blog/2017/12/5/breaking-the-chains-of-analysis-paralysis-the-black-box-part5-of-7-nftna-tdmbf-233ds-fb3jw-m2bhc-42l9m-ldjk7

Comparing several pledge managers that help with Kickstarter fulfillment:

http://www.jamesmathe.com/story-of-the-3-little-pledge-managers/

Advice for writing rulebooks that are understandable, consistent, and usable:

http://www.leagueofgamemakers.com/following-rules-is-hard-writing-rules-is-harder/

An overview of playtesting--what it is and how to do it:

https://geekandsundry.com/how-to-make-a-game-playtesting-advice-from-game-designers/

“The real danger with making rulebooks is that if the wrong rule is more intuitive than the right one then your players will never open the rulebook again.”

— Eric Yurko

“When you design a game, 1. Start with something innovative. This is your best chance to end up with something innovative.”

— Reiner Knizia

Advice for designing cooperative games from fans of the genre (audio):

https://soundcloud.com/user-318456537/coop-cast-episode-27-design-discussion-with-matt-leacock

...and from a skeptic of it (audio):

http://www.boardgamedesignlab.com/the-two-types-of-cooperative-games-with-peter-hayward/

A list of different kinds of playtesting you could perform:

https://boardgamegeek.com/blogpost/75551/defining-playtesting-part-2

How to make your game more accessible to more people (audio):

http://www.boardgamedesignlab.com/how-to-make-your-game-more-accessible-with-brandon-rollins/

Kickstarter advice from Pandasaurus Games:

https://tompetgames.wordpress.com/2018/04/09/kickstarter-tactics-with-the-creators-of-dinosaur-island/

“Go meet other designers. Play their games, have them play yours. Talk about design.”

— Chris Anderson

The role of progression in a game design:

http://makethemplay.com/index.php/2018/04/09/progression/

A list of goals you might have in mind for any given playtest:

https://boardgamegeek.com/blogpost/75622/why-are-you-playtesting

How "design patterns" can be used to guide a game toward the experience you want (audio):

http://ludology.libsyn.com/ludology-episode-173-patternity

More than 780 free emojis, useful for prototypes:

http://emoji.streamlineicons.com/

Board game design sessions from GDC 2018 (video):

https://www.gdcvault.com/search.php#&category=free&firstfocus=&keyword=%22board+game%2Bdesign%2Bday%22&conference_id=175