I am not an art expert. In fact, the only training I have had is 1 class in college - Art( For Teachers. However, I think good art has a powerful influence in children's lives. The kind of art we have in our home influences lives.
A visit to the art museum can be important but let me list some ways we can have art become a way of every day life where children can feel it's influence apart from a "once in a lifetime" field trip.
When my children were young, we went regularly to the municipal library. Besides books, this library had a collection of quality art by well known artists mounted, framed and ready to hang that could be checked out for a month at a time. The walls of my home had works by Renoir, Homer, Cassat and others displayed. I don't know if it affected our kids but I was a different person because of its refining influence.
You can also order prints from the Metropolitan Museum of Art and other places which you can have framed and mounted. Ralph got me a much loved painting for our home this way for my birthday. It is still a fixture in our home. Note: The art you choose will affect the feeling and tone of your home so choose wisely.
Children can produce their own art at a very young age. I have a daughter who hangs her children's art in her home, framed and mounted as part of the decor. Putting children's art under a magnet on the fridge has its place but framing a picture gives the creator a sense of self-esteem. She also had her children illustrate some cards so I could use them as Thank-you notes.
You need to have ample supplies easily avaiable so children can use them. As a first-time mother, I was not aware of many things. When my son drew every picure as big as the paper would allow I learned he needed glasses. Children can draw pictures before they can write words. Many of these pictures give a glimpse into the mind and soul of a child that you wouldn't have otherwise.
In kindergarten, one of our first projects was to make a book where each child drew all the pictures. I was always surprised at how many children melted into inactivity saying, "I don't know how to draw." After I showed them how to make the pictures with simple lines and circles, they were proud to show off what they had made. Often parents couldn't believe their child had done the drawings.
It is importent that children see and imitate good art. In fact, when I visited the Louvre in Paris, there were students who had set up their paints and easels in the museum so they could copy the masters. It is also important that a child be encouraged to do their own work even if it doesn't fit your mold of pre-conceived ideas.