Booking allows the water to soak and activate all the paste. It is also important to have a prepared wall. This means either primed with Shieldz or sized. The wall paper store will have a watery glue (can't think of the brand name). Brush this on instead of water.
When smoothing out the wrinkles, don't over do it. Overdoing it squeezes out the glue.
Bathrooms are even harder. Use additional paste if doing a bathroom.