Play the "uh-oh" game...
If your child continually misreads some words in context that he normally can read correctly from a practice list,  play this game.

On a piece of paper write" Uh-Oh" on the left side and "I got it" on the right. After he reads each sentence give him a tally mark for each mistake under the "Uh-Oh" side and a tally mark for each perfect sentence under the "I got it" side.  He'll pay closer attention to the words to get more "I got its" and soon stop making those errors.

Source: Preventing Misguided Reading by Jan M Burkins & Melody M. Croft