in no small part

big fish in a small pond

One who has achieved a high rank or is highly esteemed, but only in a small, relatively unimportant, or little known location or organization.

for the most part

In most aspects; mostly; generally.

in no small measure

To a very great extent.

look the part

To appear suitable for a particular kind of work, position or role.

one small step for man, one giant leap for mankind

(used imitatively) A cliché used to exaggerate an accomplishment or milestone.

play a part

To be involved in such a way to affect the outcome, to be a contributing factor.

play one's part

Synonym of play a part.

say the quiet part loud

To willingly express a sentiment that is normally considered embarrassing or disreputable to hold; to reveal an ulterior motive.