Find good references. Ask for similar sample agreements similar markups. As for past 4-5 such marked up documents. Otherwise your senior is just tripping you up to kill your confidence so that you don't rise up the food chain faster.
I am an A0 at a T1 currently. The only advice I can give you is that the more mistakes you make at your early stages in the profession, the lesser you are to repeat them further down the road. So, take it on the chin, and make sure you try to not repeat the same msiatkes you have made again.
I am an A0 who is doing this for the first time. Has been just about a month since I have been exposed to this kind of work. Got scolded/ told in a stern manner that I need to buck up and get better at this, recently for not doing a good job with the task I was assigned to do, i.e. review and mark- up an agreement. I want to endeavor to not repeat the same mistake again, and hopefully get better at it.
So, take it on the chin, and make sure you try to not repeat the same msiatkes you have made again.
How can I achieve the above?