I guess the best way to keep your mindset consistent is to balance the approach of the "winning" mindset and the "fun" mindset. You want to win because that's what a competitive player seeks, however at the end of the day you want to have fun. You want to remind yourself that you're in a great community of players and how cool it is that such a community exists. You want to laugh off the stupid tech flub moments because its a game, I laugh it off and keep my positive attitude and come back. You always want to get something out of a set, even if your opponent is worse than you. Every game is a learning experience so might as well have fun with it!