Collocations for ambitious - adj.

be, seem

extremely, fairly, very, etc.
highly
He is a highly ambitious politician.

fiercely, ruthlessly
politically, socially

for
She is very ambitious for her four children.

be, seem

extremely, fairly, very, etc.
hugely, wildly
overly
Phases 2 and 3 seem overly ambitious.

in
The book is ambitious in scope.

Ambitious is used with these nouns:
agenda, aim, effort, enterprise, entrepreneur, goal, idea, piece, plan, programme, project, proposal, scale, schedule, scheme, target, undertaking, venture, work