You are writing down the conclusion and the premise, but what are you writing for the premise? Are you writing out everything that is not the conclusion? Or are you breaking it down to the conclusion, the evidence, and the context (as the new Veritas CR book shows you how to do)?
In this article, I describe how to narrow the focus on critical reasoning.
https://www.beatthegmat.com/mba/2011/02/ ... duncan-way
The key is not to try to go fast, that will never work it adds pressure and leads to mistakes. The key is to be able to see the argument as you read it and as you assemble the conclusion and the evidence. You should notice things like changes in wording ("arrest" is not the same as "conviction") and gaps in logic.
But it all begins with separating the argument into the part that you should focus on - conclusion and evidence - and the part that you do not need to focus on but should just sort of absorb - background information.
I am writing a new article on the role of the "context" in the critical reasoning problems but I will share a little of it with you now - the reason that they have "background information" in a CR problem (and the article that I supply the link to above makes clear what I mean by background information) is there for two reasons.
1) It is there to distract you. Of course this is necessary since the question writers need to make the incorrect answers look appealing and people who focus too much on the context often get taken in by these incorrect answers.
2) The context is there to make the questions fair to everyone. For example, in the article I link to above there is a problem that I discuss that is about "sleep deprivation." Now not everyone is going to know what this is. It might be a term that is not familiar to people across all cultures. However, the context makes it clear that this is something that is bad and should be avoided, that is enough understanding to answer the question correctly. So the background information helps to level the playing field and make sure that no outside knowledge is needed on CR questions! Yet this does not mean that you should pay too much attention to the context, just let it give you any sort of general knowledge that you need in order to understand the conclusion and the evidence and then do not pay any more attention to the context. Remember if you focus on it you will be set up for the wrong answers.
Are their particular question types you are having trouble with?