I'm marking exams at the moment & this has made me think I should revisit an earlier item on writing an extended (essay-type) answer to a question.
First up: read the question carefully before you begin writing. That way you're more likely to answer what the examiner is asking, rather than what you think they're asking. There's no need to write the question out again, either; that just takes up time and doesn't earn marks. 'But my essay needs an introduction!' you say. Sure - but that introduction is a lead-in to the body of the essay & should give an introduction of what you're going to talk about or how you're going to approach the question.
(Just as an aside: a few years ago now - while I was teaching at Massey, in fact - I set a question on cetaceans - whales & dolphins. I used 'cetacea' in the question: this was a zoology paper & the students knew I expected them to be familiar with the correct names for different groups. But someone obviously wasn't. He re-wrote the question, replacing 'cetacea' with 'crustacea' - & proceeded to write an essay about crayfish! Which was not a good idea...)
Write an essay plan before you begin. Do it any way you like - notes, a concept map, a mind map: it doesn't matter. But do it. It might take 5 minutes or so. But the result will be a better-organised essay in which the ideas flow logically, the concepts are linked, and you don't leave out anything important. Remember - in Scholarship, the examiner is looking at your ability to communicate your knowledge and understanding in a clear & concise manner.
And on that issue, there are a few other things to remember. Abbreviations! Argh! I've got my own personal abbreviations that I use when I'm taking notes; I'm sure everyone has. But note the word 'personal' - I don't expect that other people are going to know what they mean, & so I don't use them in formal writing. If there's a long term that you're going to use more than once, write it out in full the first time, with the abbreviation in brackets - e.g. antidiuretiic hormone (ADH). Then everyone knows what you mean.
And you really don't want to get me started on spelling & punctuation. I don't know how many times students have said to me 'but this is Biology, not English,' when I've marked them down for poor spelling, punctuation, &/or grammar (usually it's a combination of all three). But the point is, it is English - you have to use good English to properly communicate your ideas. Too many errors here & things get a bit murky.
The other thing to do with spelling, while I think of it, is that you'll be expected to use the proper scientific terms where appropriate. Sometimes a mis-spelling here can completely change the meaning of the term: tropism & trophism is an obvious example. Use the mis-spelling often enough, & you'll leave the examiner wondering if you really know what the terms mean.
That's enough of a rant from me; I should get back to the marking. And don't be discouraged - the scholarship exams are still months & months away - plenty of time for you to work on these things so that on the day you write a set of well-crafted answers that display your knowledge & understanding to best advantage.