How do you choose what information you need to record and what to exclude? Notes need to be relevant to your topic. Apart from keeping in mind what is the purpose of note-taking at any given stage you should also make sure you record ideas that are relevant to your research topic or to the purpose to which you abide. The following questions can help you to weed out the relevant from the superfluous:
Are you clear about your own approach towards the topic?
Do you have strong feelings about the issue you investigate?
Sometimes when we scan for information our stance or ideology may get in the way and make us selective with regard to what information we record. Is this desirable? On other occasions, however, what we need to do is to scan the literature in order to find those arguments or positions that corroborate our own stance.