How should I start out a compare and contrast essay on Perry and Dick?

Certainly begin with a thesis statement about their similarities and differences. Then transition into your main ideas. This should help,

Dick uses Perry as a foil for his own self-image, often belittling or impugning him for his more eccentric, “childish,” or effeminate qualities, in comparison with which Dick convinces himself that he is “normal.” Perry, on the other hand, prides himself on being “exceptional,” sensitive, even “artistic” in comparison to Dick. However, each man looks to the other for affirmation of his own masculinity, Dick latching onto Perry for his “killer instincts,” and Perry yearning for Dick to think him “hard, as much the ‘masculine type’ as he considered Dick to be” (111).

This is an idea from gradesaver's essay suggestions. It includes the Clutters. but may give you an idea.

What is the role of family in In Cold Blood? Choose two or three characters and compare and contrast how family relationships have shaped or defined them. Does the integrity of a family symbolize something larger in the context of the book?

For the most part, within the context of Capote's book, the strength of a family seems to stem from and depend on self-determination, social status, and financial security. The Clutters are the strongest family group, and they also hold the highest position on the socioeconomic ladder. Perry, on the other hand, comes from a broken home, which helps to explain his desperate situation in the world. And Dick associates financial security with family, pledging that he will return to his first wife and their children after he has placed himself on solid financial footing. This may be because the two structures determine each other: the integrity of family dictates the strength of the individual to withstand outside pressures, while at the same time one’s ability to conquer the pressures of the world determines how unified one’s family will be.