I think one of the hardest things about teaching writing is that "head-wall-bang" feeling you get when you have taught a concept whole group, instructed on it again in small group, and they still look at you like "What is indenting?" With many areas of teaching there are ways to see immediately if a student is making growth, but in writing it can feel like a slow going process with lots of hurdles along the way.
To help myself get less frustrated, I decided to use their very first piece of writing from the beginning of the year to be my guiding light. Instead of focusing on the little details they aren't getting in the moment, I compare the piece overall to what they did at the beginning of the year - this keeps me hopeful. They may still have no clue how to write a great introduction, or the purpose of paragraphing, but man are there more details in their work than ever before, and woohoo they are finally ending with a conclusion that is not just "I stopped writing because I was done, is that not a conclusion?"
The endless challenge that accompanies writing instruction for me is the intense amount of pieces they need to get right all the time. Sometimes it feels like a lot to ask of them, but then I remember what a foundational skill this is for them - it's how they communicate with the world. There are a lot of things to look for, but sometimes I need to narrow my gaze and focus on just their details or just their conventions so I see growth and feel some success with the direction they are heading.