How was it effective?
Metaphore –
“She was a tiny wishbone of a child, with cropped hair and enormous solemn eyes—a little white owl.”
Here the author has used the metaphor “a little white owl” to describe our Else, a little girl. The use of white owl creates an effect on the viewer’s imagination that our Else is an innocent, inquisitive and bright girl. A little white owl portrays these specific thoughts because these are the ‘stereotypes/labels’ that are commonly associated with owls.

Personification –
“The Kelveys came nearer, and beside them walked their shadows, very
long, stretching right across the road with their heads in the buttercups.”

It gives the idea that they are overshadowed in their lives.

They put their heads in the buttercups as they mind their own business and ignore the other girl’s comments. It is also innocent, buttercups.

Connotative Language –
“… while they chewed their jam sandwiches out of a newspaper soaked with large red blobs.”
The use of ‘soaked with large red blobs.’ has a negative connotation. The work soaked makes the food sound less appealing, and the red blobs contribute to the distaste of the viewer. It creates an almost belittling effect, as it was a slightly comparative statement with the other girls at ‘dinner’ who had had mutton slabs in their sandwiches.

“Even the teacher had a special voice for them, and a special
smile for the other children when Lil Kelvey came up to her desk with a
bunch of dreadfully common-looking flowers.”
The use of ‘dreadfully common-looking flowers’ creates a negative connotation about the flowers and the girls.

The syntax for effects –