Consider the example sentence in the graphic above. Many writers would not see any issue with it. And yet the phrase do it is not correct here. It may be appropriate in spoken English, but as we’ll repeat time and time again, spoken English and written English are two different animals.
The appropriate expression here is do so. Thus, the writer should rewrite the sentence as follows:
It is a pronoun. Often times the phrase do it refers to an action embodied by a verb phrase (as is the case with our example sentence). Pronouns do not modify verbs. Adverbs do. Enter so stage right. So (as used here) is an adverb, and as such so can properly modify a verb or verb phrase.
While it may seem a little thing, little things do matter. Every step you take towards becoming a better writer is a step towards better writing. And better writing better represents both you as a writer and the brands connected with you.