What are the courtship and marriage patterns followed by modern Americans?

There are many as with every other country. In today's culture, young modern (12-17) children posture and preen and try to develop notice within their peer groups. By this time their hormones and bodies have begun to mature. Depending on how they express themselves, introvert or extrovertly, is demonstrated by how "depressed" or anxious they become or how energetic they become. When someone reaches 18-28 they are now developing their own styles (as they've imagined themselves to be) and creating new peer groups from social groups and work groups. This period is usually characterized (51% of the time) by numerous group joinings, outside events (concerts, nightclubs), and social communications. While this the number getting married during this period has fallen in recent years, there are a lot of informal living arrangements made. Once past this phase, and hopefully established in a career of choice, the hormone levels drop, their remaining friends of their social and peer groups have diminished (or they've gotten married), and men tend to marry by age 32 and women by 27. They look for stability, they look for work habits, and they look for advancement (called gold diggers (male and female) by many). Most adults get married during this period at least for the first time.

While there has been a lot of "women's liberation" over the past 20 years, many young women use their parents as role models when they go courting. Either actively or passively. If they came from stable successful marriages they will look for a partner that promises them the same result. If they come from a broken family, they will often seek a radically different type of partner or living arrangement. Young women are increasingly trying out all manner of lifestyles to say that they "did it" and then settle down to more traditional marriages.

Different cultures within the US (some 2-300 of them) have different techniques and control mechanisms (rites of passage) for their children, so the answer to this question will vary by culture, race, and religion. Lack of homogenity is a strength and weakness in the US.