Flash games have become one of the most popular attractions on the internet in recent years. Thanks to their growing popularity it's now entirely possible to sell your own flash game for money. One of the reasons that flash games have become so popular is the fact that you can play them directly from your web browser. This eliminates the need to download or install third-party software, and also allows the player to multi-task and continues surfing the Internet while playing the game.
First, conceptualize your idea and what kind of market you're going after. There are millions of different games on the internet that appeal to different tastes and therefore different markets. Write your conceptualized idea down in the center of a piece of paper and begin to brainstorm. Any idea that you have for your game would go into this brainstorm. That means anything from major plot elements to superfluous details.
Then, design your game. Include all of the elements that you brainstormed. When designing a game you want to keep it simple but challenging. Make it challenging enough to keep the players' interest but not too challenging for an average internet user to complete. Half the appeal of games is that they are not as complicated as console games and installable computer games. Also, unless you're explicitly reaching out to an adult audience, keep the game safe for work meaning no adult themes.
Copyright your game. This will legally protect your flash game from being reproduced or copied by outside developers without your exclusive permission. Having your game copyright protected means that you own the full rights to your game and have the right to file a lawsuit against any company or individual that copies your game without your explicit written consent.
Market your game to sponsors. In order to make money off of your flash game you want someone to sponsor it or buy it. If your game is deemed to be good enough by sponsors they will want to have it on their web site. There are web sites which allow you to market your game to possible sponsors
Last, compare and contrast whether you want a flat-rate buyer or a sponsorship deal. A sponsorship will pay less up-front than a buyer because a sponsor would be "renting" the game from you to put on their site. This means that they may pay you more over a long period of time if your game is popular. An up-front buyer will want to buy the exclusive rights to the game.