The way you should approach the office action response depends on the examiner’s reasoning. The two most common approaches are a legal argument challenging the descriptiveness finding, or evidence supporting acquired distinctiveness.
If you’re arguing the mark is suggestive, you should explain specifically why the connection between the mark and the goods requires imagination or inference, and cite comparable marks that have been registered despite superficial similarity to descriptive terms.
If you’re arguing the mark is distinctive, you should submit evidence of long and exclusive commercial use. Things like sales data, advertising expenditure, market share, consumer surveys, and third-party recognition of the mark as a brand rather than a generic term can all help.
If neither argument is strong, amending to the Supplemental Register avoids a final refusal while allowing the mark to build commercial recognition over time.