A noun is a person, place or thing ... so which of these words are a person, place or thing?
First, the runners wait for the signal to start.
It can't be first because that's not a person or place or thing. The is just a modifier, so none of those are nouns. Runners are people so that's a noun. Wait is an action word, a verb. For is a linking word so that's not it. Signal is a thing so that's a noun. To start is another verb.
runners - noun
signal - noun
first - adverb
the - definite-article
wait - verb
for - preposition
to - preposition
start - verb
The first word of a sentence must start with a capital letter. There are millions of ways to start a sentence!
First think about what you first know about the subject
It's not generally done, no.
you say first, because firstly is not a word
Yes.
Only if it's the first word in a sentence.
Sure, as long as the beginning word has a capitalized first letter.
One way is........
you should start of by pacing yourself slowly and when you see the other runners getting slower sprint fast
Not necessarily, if it is the start of a sentence or if it is a word that is usually capitalised, you would. But if it is a quote and you start say in the middle of the sentence then you don't.
No, a sentence can begin with any kind of word. The first letter of a sentence is always capitalized to mark the start of the individual sentence, not because the word is a proper noun.
You need to write the story first, and worry about the first sentence after you've got the whole thing down! Just start writing and come back to change your first sentence later if you want to make it more interesting!