disco - is it a patterned paper that you need to align? If so get that edge right and brush away from it with something like this
http://www.screwfix.c...528?_requestid=706679
and use a seam roller - then a damp cloth to remove any glue squeezed from joint.
Another reason for bubbles is not laying paper perpendicular - do not start in a corner believing that to be "square" - mark a line usings a chalk line, plumb bob or spirit level one paper width away from corner, and cut paper into corner. Also for best results, start in the lightest part of room i.e next to window and paper into room - hope that all makes sense - if not ask again