Knowing how to write law essays and short answers can be done by knowing what is good academic writing. You can start with learning how to write a good introduction. Knowing how to acknowledge your sources is also essential. Further, you also need to develop the skill of critical use of source materials. Expressing caution is also important. After all these, you have to develop the knowledge and skill of revising your text which involves redrafting, editing and proofreading. Later, you will also need to continually improve your writing.
Writing law essays and short answers is aimed at letting you develop your writing skills specifically planning, drafting and revising your work. You should know how to meet criteria on which your writing is evaluated. Your writing should have the typical components of academic work. Knowledge on how you organise the components of your text should also be demonstrated by you in your work.