I have no idea what sort of cases you will be hearing, but here are a few suggestions. By the way, I am a retired attorney.
1) Make sure your judgment recites the important facts of the case in detail. This is important because the next case involving this area of the law might have a significant factual difference from this one and that might change whether your judgment is relevant to that case.
2) Look for other cases on similar points and explain why they do or do not dictate the answer in your case.
3) Be sure not to let your own personal opinions into the judgment.
4) In applying the law, look not only at the exact wording of the law, but also at any evidence you have as to what the lawmakers meant.
5) Don't try to write a sweeping judgment. Decide THIS case.
I hope this is helpful.