Now that we know how valuable it is to do a playtest, you may wonder how to go about doing one. First, I do want to note that it is vitally important that you are in the room while your project is being playtested. While they are playing the game, you can see not only what someone thinks, but also how they react to things as well as what they do with your game. This is the time where you find out what works well and what doesn't. If for some reason, you are unable to be there in person, have them record themselves playing, both on the PC and from the webcam if possible.

When someone comes to a computer to playtest your game, you may be tempted to tell them things about your project, such as the controls and the story, and the mechanics, and anything else, but you should resist these urges. See what the player does without any prompting to begin with. This will give you an idea of what players will want to do naturally given the environment that you created and what needs to be explained more. Once they play for a while and you've gotten the information you need on that end, then you can tell them some things.

When playtesting, it's a good idea to get as much information from the player as you can. When they finish, ask them what they liked, what they disliked, if they found anything confusing, where they got stuck, and what was the most interesting thing to them. Do note that what a player says and what they actually do are two different things, so it's important that you are there and watching them. Getting your game played and seeing what those players do is where you will start to see the cracks in your design's form, and seeing what people do will show how they experience the things you have created. While doing this testing, I've seen a lot of people do the exact opposite of what I expected and not understand something that I thought was quite simple. The player isn't wrong in this regard though, I was. The player can only do what they know from prior playing or from what is taught in the game.

All of the information that you get during a playtest is important. Not just what they say, but also what they don't say. Once they finish playing, give them a survey to fill out. I find using Google Sheets does a good job at storing this information and isn't too difficult to set up, and you have hard data from which you can make decisions without having to remember what people say. Plus, it's a lot easier for people to select a number from 1-10 for how they enjoyed different aspects of the game than to ask their thoughts for everything and doesn't require them to write paragraphs of info (unless they want to in a comments section at the end).

In addition, the order in which players give their feedback is also important as it communicates how important different things are to them. You may find that what was intended to be the main mechanic isn't as engaging and/or fun as something else. That is valuable feedback, and you may decide to focus on that secondary mechanic instead for the title, as I've seen happen repeatedly on projects. It's better to do this as early as possible so you will waste as little of your time as possible.