Your goal: to be admitted into your dream client's company, his tribe. A tribe is a complex social group, an organism with a culture and rules of its own. Here's how to break in:
Build relationships with tribe members. You aren't going to become a member of your client's tribe without sponsors. Someone is going to have to vouch for you. Your sponsors are going to have to prove that you are a valuable addition to the tribe before you are invited in. You are going to have to prove that you share the tribe's values, that you share their goals and that you will abide the tribe's norms and customs.
You are going to be tested. Some tribe members are going to be skeptical of you. Outsiders who don't share the tribe's culture, values, beliefs and goals are a threat to the tribe. You need relationships so you can prove that you belong. You need meaningful relationships with tribal members who will support your admission to the tribe.
Understand the tribe's hierarchy. Different members of the tribe have different roles. There is a tribal hierarchy. Navigating your way through the tribal politics requires that you understand the tribal hierarchy.
If someone lower down in the tribal hierarchy invites you near the tribe, you are going to have to work your way up to the higher-level relationships within the tribe. If your relationship is with a tribal leader, you can expect to be greeted with skepticism from deep within the tribe, at least until you can prove that you care as much about the tribe as you care about your relationship with the tribal leader. You will need to navigate the tribe's political structure.