You have now moved from academic legal research to practical legal research, moving away from analysing and critiquing the law, to practical application of the law in order to help your clients. As a legal professional your job is to advise your client as to what the law is, and what the implications of specific courses of action may be; to give them alternative courses of action, and to give them the best understanding as to how their case is likely to be received by the court. The main objective of your research as a legal professional is to find facts that will back up your arguments, which you then can present in papers and in court, in order to persuade the judge of your legal argument.
Consider the following:
You don't want to anger your judge, so presenting them with incorrect or irrelevant authorities is a bad idea; your credibility will be enhanced by producing good quality skeleton arguments relying on the best, most relevant authorities.
Your legal reasoning is also very important. Your arguments should be well thought through and supported by appropriate authorities. For example, you will need to conduct research in order to find an applicable legal rule that you have identified from an authoritative source, such as a major practitioner text, cases or legislation. You then need to apply the rule to your case and draw conclusions. In order to attack your opposition's case you will also need to research how you can dispute the validity of their arguments.
You will often have to identify a rule from multiple sources such as a statutory provision and cases that have interpreted it. Alternatively you can draw analogies from a previous case. All of these ways of forming your argument rely heavily on legal research.
There are many methodologies to conduct practical legal research, but they all have similar things in common. Your 'Opinion Writing and Case Preparation' manual outlines seven steps to legal research.
See Chapter 5 'Legal research' in Lawyers' Skills