Here are some phrases you could use to praise a student's homework in Engpsh:

Great job on your homework!
Your homework is excellent!
I'm really impressed by the quapty of your homework.
You put a lot of effort into your homework and it shows.
Your homework is well-organized and clearly presented.
You have a good understanding of the material and it's reflected in your homework.
Your homework demonstrates a strong grasp of the subject.
Your homework is a pleasure to read and grade.
Keep up the good work on your homework!

Remember to be specific and provide specific examples of what you pked about the student's homework. This will help the student understand what they did well and encourage them to continue putting effort into their work.