W. Eric Martin had a very, very good interview with legendary game designer Reiner Knizia. You can watch the entirety of it above or at the original BoardGameGeek post. I pulled out a handful of quotes that I thought were relevant for designers at all levels of their career.
On understanding the production side of things:
"If you’re going to do good game design, you must understand a lot of things. What can be afforded, what can be put in, how quickly can you do it if you work to a deadline."
On global licensing:
"Once you have put in a lot of energy into creating an IP, creating a game, it is most natural to not only market it in one market, but to market it worldwide."
On starting with small publishers:
"Getting your first game published is always a very wide step. I was lucky that I went with small publishers. If you go with small publishers, they take you seriously and you learn from them. A small publisher cannot afford a flop."
On "failed" designs:
"Most of my ideas die in the first hour… Is this a failure? I don’t call it a failure. It’s an experiment… The problem is in your head, everything works.... It is very important to realize when something doesn’t work. I have two or three designs where I didn’t want to believe it doesn’t work. Then you come into this sunk cost fallacy stuff. These are the real dangers, when you fall in love with your design too much."
On design goals:
"What I want to achieve: Simple games, but then the people bring themselves into it. And you see out of the simplicity, a second level of depth. That keeps you playing."
On how theme and game are conflated:
"I took a game to America, Tutankhamun, I opened it and the publisher said ‘Ah, we already have an Egyptian game, we don’t need that.’ A few weeks later, I show a German publisher, they say “Ah, we already have an Egyptian theme, so we might not take that theme, but let us see the game first.’ At that time I realized what people see as a game are completely different things."
On 'tabletop vs. electronic' dichotomy:
"Board games do not compete with electronic games. That’s far too narrow a view. Games compete with other leisure experiences."
On making relevant games:
"Books and games are, for me, a mirror of our time… If you want to make relevant games, you need to look around and see what happens in the world and then reflect that in the games. Not only from a theme point of view, but from a dynamics point of view."