Actually I know that this might surprise you (it really surprised me anyway), but Stephen LaBerges original Wake Back to Bed goes like this.

1. Set you alarm - Before going to bed, set your alarm to awaken you two to three hours earlier than usual, and go to sleep at your normal time.
2.Get out of bed promptly in the morning - When your alarm goes off, get out of bed immediately. You are going to stay awake for two to three hours. Go about you business until about a half hour before returning to bed.
3. Focus on your intention for your lucid dreams - blablabla he described the MILD technique.

But as you can see the optimal WBTB (stay up) time is 2-3 hours, according to his experiments. How long is your WBTB time and when do you do it? =)