But the biggest change I made was actually writing down the mistakes
I've been learning mandarin for a couple of months and I do something similar.
My girlfriend can speak it so what I do is speak mandarin during our suppertime every day and I have google translate beside me. If there are words I can't say and want to remember later, I star the translation and add it to an Anki deck later on.
I haven't really figured out a lightway way to capture problems with forming whole sentences, though. It kind of breaks the flow the conversation too much if I'm writing down whole sentences.
Do you capture only problems with remembering specific words or also problems with forming whole sentences?