Ensure that there is unity in your writing

Decide the angle of the subject you will focus on.
Focus your writing on a small area you can conveniently handle while simultaneously gripping your readers. An unwieldy writing task will drain your enthusiasm.

Use your tenses properly.
Write in the past, present, or future tense. You can also use more than one tense in your writing, but avoid switching them back and forth as this might keep the readers confused.

Use a coherent mood throughout your writing.
Your mood can be casual, formal, witty, sarcastic, sincere, sad, optimistic, and pessimistic, but avoid mixing two or three tones especially in short writing.

Be consistent with pronouns.
It's ok to convey your message as the first person, second person, third person, participant, or observer, but avoid mixing too many pronouns in a single writing.

Compress your ideas.
Distill your narrative coherently from your huge and tangled mass of experiences, feelings, and memories.