Increasing time on task for success

If “time on task” is key to success, how can you increase that time? The best artists are those who have spent the most time practicing art. The best historians are those who have watched the most history channel, spent the most time pouring over primary documents, read the most historical fiction. The best writers are those who have written the most and gotten the best feedback on their writing. How can you help students put in more hours in your subject? And perhaps more importantly, how can you get them interested enough that they are willing to put in the time?