Factors and consequences of group cohesiveness?

Factors may include;
Individual differences. At interview stage, its possible to seek out people who will fit well into a team.
How people are treat by management; is the reward scheme consistant and fair?
Will there be a clash of cultures?

The main consequence will be that workers are likley to feel more motivated, when they are in a strong team.

Search forming, norming and storming, this may help