keep it together

band together

to unite, to come together

bang some heads together

Attempt to get results from a previously ineffectual or argumentative group, typically by coercion or force.

birds of a feather flock together

People of similar character, background or taste tend to congregate or associate with one another; it is easier to establish friendships with people that one has a lot in common with.

bring together

To cause people to do something together; to bring about togetherness.

cobbler, keep to your last

One should not criticise matters outside one's field of expertise; one should mind one's business.

earn one's keep

To perform satisfactory physical labor or to provide other worthy services in return for remuneration, lodging, or other benefits; to support oneself financially.

get one's act together

To become serious, organized, worthwhile, etc.

get one's shit together

To organize oneself in order to be able to deal with or achieve something; to mature.