What special preparation does Gatsby make for having tea with Daisy at Nick's cottage?

Gatsby is extremely nervous about his forthcoming meeting with Daisy. He has the grass cut in front of Nick's home and then fills the cottage with flowers from his greenhouse. All of Gatsby's agitation is largely intended to explain why he has taken such roundabout means of obtaining a meeting with Daisy. He has built a mansion and holds extravagant parties every week with the hope that Daisy might show up at one of them. This, of course, gives F. Scott Fitzgerald an opportunity to describes the kind of behavior that is so much associated with the Roaring Twenties,, a spree which itself was doomed to end in disillusionment and disaster.

Gatsby is supposed to be a tough guy, and ordinarily he is cool and poised. But Daisy makes him feel and act like a high-school boy on his first date. She is a dream, an illusion, a fantasy. He has a totally unrealistic picture of her. She never really does or says anything out of the ordinary. She is just a pretty girl, but she represents the upper class to which Gatsby aspires to rise and to which he knows he does not really belong. 

It is possible to climb one rung up the social ladder in American life. It is even possible to climb two. But it is impossible for any young man from the bottom class to climb all the way to the top in one lifetime. We see how Clyde Griffiths' life ends tragically in Theodore Dreiser's great masterpiece An American Tragedy (1925). William Dean Howells writes about the same internal and external obstacles to upward social mobility in The Rise of Silas Lapham  (1885). William Makepeace Thackeray dealt with the theme in The Luck of Barry Lyndon (1844), as did Stendhal in Le Rouge et Le Noir (The Red and the Black) in that 1830 novel.

All of Gatsby's preparations for his long-awaited meeting with Daisy show his inferiority complex and his false position in Daisy's world. He never had a chance to fulfill his dreams about winning her away from her husband and daughter or from the Olympian world in which she was one of the demigoddesses.