A lot of it is just patience.

I use roughly the same postion (palms to my sides), and just look forward, but the biggest factor is staying awake long enough. Just relax and think about something involving, such as riding a bike or swimming. Something that involves all of the senses. This will keep you conscious and awake when you'd normally drift off to sleep. It will take a while, sometimes more than a half an hour, but it's worth it.