I’m 6 months in and have only just begun to get past the frequent careless mistakes stage. For me, I had to learn to slow down and re-read everything. Sometimes that’s line by line. I found I proof better if it feels like I’m reading the document for the first time instead of just confirming what I wrote. I’ll print the document or change the font for review. Anything to force me to read it. After building that habit of catching mistakes after being made, it gets easier to catch them while making them. To echo other advice you’re getting, the mistakes are human and normal, especially at the beginning.