Understatement is always best. Analogies in writing are like feathers on a snake. The passive voice is to be avoided. Go around the barn at high noon, to avoid colloquialisms. Even if a mixed metaphor sings, it should be derailed.
Exaggeration is a billion times worse than understatement.
Don't never use a double negation. Capitalize every sentence and remember to end it with a point 24. Do not put statements in the negative form. Verbs have to agree with their subjects. Proofread very carefully to see if you words out.