Unity means consistency. Choose how you are going to write your article and write it in this way from beginning to end.
1) Unity of pronoun
Are you going to write in first, second or third person? Avoid mixing them up unless you want to make a serious point about something.
2) Unity of tense
Most writers write in past tense. It depends what event you are describing. Choose a tense and stick to its anchor. Of course if you write in past tense, occasionally the need for past perfect tense will appear. That’s OK. Just know past tense is your preferred tense.
3) Unity of tone or mood
What’s the mood of the article? Is it sad, upbeat or serious and official? Choose one and stick to it. Only deviate from it intentionally.
4) A few other stylistic points
- Write out the numbers 1-9 in words: Instead of 1, write one.
- Write the numbers for any other number
- Never start a sentence with a number