How can I change my students from bad readers into good ones?

Try asking their interests. what kind of books they would like to read for example fantasy, fiction, horror or thrillers. You can also judge your students interests by asking them about the movies they like and why. This will give you an insight about the student's capabilities. Make a game with the student. Instead of saying "this is your homework", tell them "i read something which i know you would enjoy. it's very interesting....did you know that..."

Such sentences are bound to gain the curiosity of the students, and once they say they have read the topic, ask them questions about it. Then see where the problem lies which hinders their understanding. If its the grammer than start focusing on that.....