Here is a link to spelling word activities that may help your child learn to spell and help him/her want to practice spelling words.  These would also work with the words to know (sight words).  

https://specialedresource.com/multisensory-spelling-activities

 Also, you could focus on 3 words each night so that practice time is shorter and students may be more motivated to practice.

Another idea is to start a reward chart.  Each time your child practices the words, he/she could earn a sticker, star, etc. on a chart.  After a certain number of stickers, he/she could earn a prize or a privilege- ice cream, a small toy, time to play a video game, choosing the movie the family watches, .....