I am a recently retired university lecturer, but would find it difficult to answer your question wtihin 150 words. You might find it helpful to look up 'critiquing frameworks' on the internet, which provide a set of criteria for being evaluative and critical. The subject area you are studying is relevant as there are different frameworks for different subject areas. I would recommend that you seek guidance from your tutor, especially if it is they who will be marking your work- that's what they should be there for, at the end of the day!

I'm doing my masters at mo - studying can be a frikkin nightmare!!! Sometimes when I get stuck I kook thru key peices of work (notes etc) then write out bullet points - could be as simple as 1. Evaluate 2. Critique 3. Recommend. Then I put everything away and give myself one hour to write ANYTHING - but I try and keep writinng - usually (hopefully) something will come out of it you can work on. Half the battle is getting any words down on the page. Good luck