1. Let the reader choose the reading material.
There is much more motivation to read when the material is of interest to the reader. No one enjoys struggling to do something they have no interest in. When the prize is learning more about a hobby or something else of interest, the joy of learning is worth the hard work. It may be history, transformers, animals, mystery stories or anything else of interest. Motivation is key.
2. Keep it short.
Spraining the brain does no good. Short, frequent reading sessions are much more effective. Stopping at a point that leaves the reader wanting to know more also helps to keep up interest.
3. Break it up
Struggling readers often have trouble following the story line or the flow of information. Decoding the words take so much concentration that the point of reading, to enjoy a story or learn something new, can be lost. Try having the reader read the every other sentence or paragraph. Often when reading with my son I have him read the first sentence of each paragraph aloud.. Then I read the rest of the paragraph aloud. This keeps him practicing, yet keeps him from losing the point of the passage we are reading because he has to struggle with each word.
While it is very important to me (as I know it is to most parents) that my child learn to read well, it is even more important that he retains the love of learning that he now has. These are things we have done to strike a balance between the two.