I don't know of a website, but maybe this will help:
Keys to motivating learners:
 Invest them in the topic. Make it relevant to them so that they choose/want to learn it.
 Set them up for success. Tell them what they are going to do, how they are going to do it, and why you want them to do it.
 Support them. Acknowledge their efforts, listen to their ideas, correct them, feed in new language, and interact with them on a personal level.
 Give them feedback. Ask them how they think they did, tell them how you think they did. Highlight their good and bad uses of language. Show them their strengths and weaknesses and what to improve and how to improve; i.e., self-study strategies.
- For Teachers