Maybe I'm projecting, but when I sit down to playtest with people who know me from my online presence, I feel like they are invariably disappointed. You could probably read this blog and come away with the impression that I am good at game design, or that having me as a playtester will yield helpful insights.
The truth is, if I am smart at all, I am only smart about a very narrow band of topics. I have a hard time with rules complexity and strategy as a player, and that comes out in my designs. Fortunately, there are a few things I've gotten better at which make me a more effective designer and playtester.
One thing writing this blog has done is make me a better communicator. I've found this skill helpful when playtesting games by other designers, because I am able to articulate what parts of the game didn't work and why I think they didn't work. As a designer, I'm still working on how I teach my games to playtesters and communicate affordances in the components and rules. Sometimes I succeed better than others.
The good news is that this is a skill every designer can improve on. We all have our weak areas, but strong communication skills can help us show off our design strengths. A good way to do this is to playtest your rules teach. Learning to give the players the correct amount of information in a useful order will make you a better designer and help you when you go to write your rulebook.
Playtesting your teach means you have to be comfortable enough with your game rules that you can not only convey them to players, but you really need to be able to simultaneously pay attention to the players to ensure that you are aware of any confusion that occurs. You may want to practice on people you know before practicing your teach on strangers. I'd also recommend being a playtester for designers who have a number of published designs. Pay attention to how they run the playtest. Heck, take notes.
Another way that communication is important is within the design itself. We talk about player confusion a lot, but another way of describing player confusion is to say that the design is doing a poor job of communicating with the players. You may have found that your design will go through a phase where all you are fixing is graphical issues until you hit a point where players begin having issues with mechanics again. Most players won't be able to give feedback on mechanics when there are glaring usability problems. Eliminating those problems allows the game to communicate better with the players and thus the players are more able to give structural feedback about systems.
Becoming a better communicator will make you a better designer. All it takes is some practice.
ShippBoard Games is a board game design blog that updates most Mondays.