Where do you live? larger flower beds with colorful shrubs azaleas, rhododendrons would be lovely and hosts under the tree between the walk and the house. Unless you need more light in the house, why would you go to the expense of enlarging the windows? Like edwmoms comment.

I would suggest you add a matching window where you now have a vine growing on a trellis. I also would suggest you move the bay window to the wall where the high triple windows are and put a plain window in place of the bay that matches the second-story window above it. i Ialso believe a light green roof will bring a fresher look to the exterior. The blue door another poster suggested might work, but you also might consider a light lemon yellow.