JP- one would hope a barrister would think a bit more practically than a law student would in a problem question! But otherwise clearly all of the points you make are right (and obviously I know what you're getting at vis a vis the "barrister" comment).
Regarding essay questions; it is much more difficult to describe the process of writing a first class answer. Unlike problem questions, which are highly methodical and require rigorous scrutiny of the facts of the problem (and sometimes the case law), essay questions require much more of a personal touch and can be answered in many different ways. People talk about vague concepts such as "originality" and "offering your own opinion", but ultimately I also think a first class essay will have an element of "swagger" that a 2.1 simply won't contain. It took me until 3rd year (and a number of failed experiments) before I finally unlocked the secret to writing consistent first class legal essays, so if you're in the first (or even second) year and struggling to get those firsts, I certainly wouldn't become too discouraged.
Things to bear in mind:
1. Always lay out your arguments in the introduction. E.g.- first I will address this, second this, and finally I will examine this.
2. Make a limited number of detailed arguments. This is likely to demonstrate greater understanding of the topic and also lends a natural structure to your essay. It is also better in exams, particularly as you only have limited time. Do not adopt a "scatter-gun" approach, whereby you offer a multitude of different points, all of which are supplemented by sketchy details. Essays written like that tend to demonstrate a lack of comprehension of the subject-matter and are also usually very disorganised.
3. This is where it becomes a bit tougher to describe. I suppose the best I can do is to say that, try and make the examiner aware that the essay sets out your arguments, and not say an academic or judge's. When quoting from extraneous sources, always make sure their pearls of wisdom (or idiocy) are seamlessly interwoven within the fabric of your essay (and not vice versa). Engage in the academic debate, and state why you feel a particular viewpoint supports or contradicts your own. If the article runs counter to your own beliefs, explain why you are right and the academic is wrong. Be respectful, but don't be afraid to criticise, even if the individual in question is a Supreme Court judge and you're a first year student.
4. Try and think of something a bit different if you can. It might well set you apart. Getting a first can sometimes be about going beyond the usual. For instance, in my final year we had a Company law question about whether the Courts' approach to piercing the corporate veil was correct. Most people stuck to English jurisprudence and commentary when answering. I decided to dedicate one of my paragraphs to a comparison between English and US and Commonwealth jurisprudence and went on a bit of a rant about how the Australians had got it right, whereas we had got it wrong! It's that kind of touch that will get you into the 70s. You also might want to sprinkle a few gobbets here and there to prove you have a read a judgment in detail etc...essay writing really is about showing off sometimes!
5. Read academic articles and ape their style. The more you read the better. Don't go mad and spend all year in the library; I certainly didn't- but pay attention to common essay structures, legal academic jargon and particular ways of expressing things. Stylistically it can make a difference.
Just a trivial example:
Student A- "The case of Williams v. Roffey Bros was about whether factual and practical benefits could constitute good consideration."
Student B "Williams v. Roffey turned on, inter alia, whether factual and practical benefits constituted good consideration."
They say the same thing but silly as it sounds, I'd take Student B more seriously, because he is using legal phraseology (i.e. "turned" rather than "is about"). Things like that establish from the beginning that you intend to be taken seriously.
Right that is my contribution- otherwise, just see what works through trial and error!