What does Helen mean by "everything has a lesson and a suggestion" in The Story of My Life?

When Anne Sullivan comes to Helen Keller, she opens up whole new worlds of learning. Despite the fact that little Helen is blind and deaf, Miss Sullivan teaches her language by spelling words into her hand and showing her what they meant. Soon after that, Helen can make sentences. Miss Sullivan helps Helen see the world by describing things to her.

Helen has a great love of nature, so she and Miss Sullivan go outside...

When Anne Sullivan comes to Helen Keller, she opens up whole new worlds of learning. Despite the fact that little Helen is blind and deaf, Miss Sullivan teaches her language by spelling words into her hand and showing her what they meant. Soon after that, Helen can make sentences. Miss Sullivan helps Helen see the world by describing things to her.

Helen has a great love of nature, so she and Miss Sullivan go outside as much as possible. This makes their lessons more sensory and interesting for Helen.

All my early lessons have in them the breath of the woods–the fine, resinous odour of pine needles, blended with the perfume of wild grapes. Seated in the gracious shade of a wild tulip tree, I learned to think that everything has a lesson and a suggestion. "The loveliness of things taught me all their use" (Chapter 7).

Helen can tell there is a lot to experience outside in nature. The combination of the senses she can use and Anne Sullivan’s descriptions allows her to explore the world around her. When she says there is a lesson in everything, she means she is finally able to experience the world on a fuller level now that she has the use of language and someone to explain things to her.

Nature seems to make learning almost any subject easier and more interesting for Helen.

There we spent many happy hours and played at learning geography. I built dams of pebbles, made islands and lakes, and dug river-beds, all for fun, and never dreamed that I was learning a lesson. I listened with increasing wonder to Miss Sullivan's descriptions of the great round world with its burning mountains, buried cities, moving rivers of ice, and many other things as strange (Chapter 7).

While she enjoys studying zoology and botany and using the great outdoors to explore other subjects, Helen has less patience with arithmetic. Anne Sullivan teaches Helen arithmetic by counting beads. She learns to add and subtract this way, but likes going out into nature more.