ooh, talking of Oxford commas, I'm getting frustrated with Word and its "English (UK)" grammar check!
My sentence reads:
'Start with very small fluctuations up and down, and gradually expand the range until they are covering their full vocal range.'
First, it tells me that i shouldn't be uising the comma after down, then it tells me that if I must use it, then I should put:
'Starts with very small fluctuations up and down, and gradually expand the range until they are covering their full vocal range. '
or:
'Start with very small fluctuations up and down, and gradually expands the range until they are covering their full vocal range.'
Because obviously, everyone knows that if you're giving a command, you change into 3rd person halfway through the sentence, don't you!
PS: I've noticed that I use the " by habit, and using the ' instead when it's not an apostrophe feels very weird to my typing hands 