How does Gatsby's ambiton come into play? I have that he hides his true colours as he only wants to meet Daisy at his house. I need help expanding that.
Gatsby's entire personality is a creation. He changed his name. He gets involved in organized crime (mostly drugs and bootlegging) in order to obtain enough wealth to be worthy of someone in Daisy's social class and strata. He holds social elite parties only in order to establish himself in social circles that Daisy might be a part of. Judging by the fact that he had no friends come to his funeral, it is clear that he made no meaningful connections at these parties. All the relationships he established were just a means to the end of getting to Daisy.
Nick describes Gatsby's project of winning Daisy back as the "following of a grail" in Chapter 8. His one ambition is to win Daisy back and he will go to any lengths in order to do so. Meeting her is just one step in a long series of efforts to make this happen. He chose the house he lives in because of its close proximity to Daisy. He built his life around this one dream. Gatsby's chase of this grail is evocative of chasing the American Dream. Unfortunately for Gatsby, his relatively innocent ambition is so strong that he is oblivious or indifferent to the dangerous positions he has put himself in: being involved in organized crime, having an affair with a married woman whose husband is also having an affair.