How to do Affinity Estimation?

Affinity estimation is just a technique by which story points are assigned to user stories. It’s not an agile methodology. Clients expect estimates and we need to be able to provide them to remain competitive. So, why don’t we do it as best we can? Being practitioners of agile methodologies, we’re already past giving estimates in days and hours, but even story-point estimation can be tricky for all but the most experienced teams. We need a better solution and affinity estimation may be a step in improving software estimation for us all.