Carla Madrigal knew nobody in Seattle when she moved there last year after 38 years in San Francisco. She wanted to make new friends. "It was pretty devastating to be so anonymous," the 68-year-old artist says.

To meet people, Ms. Madrigal made herself get out of the house every day. She joined a gym and a community garden, took yoga classes and visited a teahouse. And although she considers herself a shy person, she struck up conversations on the bus and at the grocery.

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