The link above is to a blog written by Walter Chen for Buffer.com. The information is familiar to me from my doctoral research on learning and memory, but he has presented it in a very simple way in his blog and I think it is helpful for everyone, and especially language learners and language improvers (you already know the language, you're just working on improving it).
I have always incorporated "looking for the positives" into teaching speaking skills. It's much easier for people to dwell on their mistakes and overlook the things they did well because the negatives are right in front of their faces but the positives are not. I help people practice how to "look for the absence of a negative as a positive."
Why? Because when you are understood, nobody tells you, "That was great, I understood everything you said." The listener just understands you and the conversation moves on, they reply to you, you get the correct food that you ordered, your professor understood your question, your supervisor understood your comment, your audience nods their heads in understanding, etc.
However, if someone doesn't understand you when you're speaking, they will tell you or give you nonverbal signals. You have to be mindful of the moment. If you weren't asked to repeat a word, nobody asked you "What?" or your listener didn't make a confused face while you were speaking, those are all positives in a place where negatives could have been.
Once you notice this, you should take a moment to appreciate and celebrate it, keep a record of it. Keeping a very simple list of a few "times I was understood today" keeps your mind focused on those positive moments instead of the negative. I can help you learn strategies for how to evaluate the times there was misunderstanding and make improvements for future interactions, but that should always be balanced by the successful interactions.
Noticing the positive moments creates a different perspective about yourself as a speaker and how you are perceived by others. It creates confidence that you will be understood and that creates motivation to seek more interactions and the more you interact and speak with people, the better speaker you become and a positive spiral is created. Spiral upwards by being mindful of the positive moments.