In Anne Tyler's Saint Maybe, Ian is described throughout the first five chapters.
Just in Chapter One, we learn several things about Ian Bedloe...
...Ian was seventeen and...large-boned, handsome and easy-going, quick to make friends, fond of a good time.
I would choose the word "easy-going" to best describe Ian in this quote.
Ian is also described as follows:
He was bright, his teachers said, but lazy.
Based upon how Ian develops over the course of the story, the one word that would best describe him would be "bright."
Crowds of loyal friends had surrounded him since kindergarten.
This description infers that Ian is well-liked and a good friend because of use of the word "loyal." So I would describe Ian as "respected."
Ian is something of a day-dreamer, as noted in the following quote; we could describe Ian, then, as a "dreamer:"
...sometimes Ian daydreamed about pitching for the Orioles.
Ian has a vivid imagination as seen when he first meets Lucy, his brother Dan's girlfriend—seeing her resemblance to a bird.
To Ian, Lucy resembled some brightly feathered bird held captive by his brown-plaid family. Her face was very small: a cameo face...She wore extremely red lipstick that seemed not gaudy for some reason, but brave. Ian was entranced.
This quote also indicates that Ian is observant, kind-spirited (in that her lipstick would make him think her "brave" rather than "gaudy") and accepting because he is "entranced" upon their first meeting.
Perhaps the most interesting thing about these quotes is that most of them paint an accurate picture of the man Ian grows to be throughout the novel—perhaps with the exception of being a day-dreamer. It does not take too long before Ian is forced to come down to earth with a thud, but he remains a gentle soul who gives his heart over quickly.