5 key factors.

After exhaustive research by Google as to what make a great team.

1. Psychological safety: Can we take risks on this team without feeling insecure or embarrassed?
2. Dependability: Can we count on each other to do high quality work on time?
3. Structure & clarity: Are goals, roles, and execution plans on our team clear?
4. Meaning of work: Are we working on something that is personally important for each of us?
5. Impact of work: Do we fundamentally believe that the work we’re doing matters?

Further reading if you like:

https://rework.withgoogle.com/blog/five-keys-to-a-successful-google-team/