Don't attempt to work around a corner using a single length of wallpaper - it will just crease, bubble and even tear, and, because corner edges are seldom straight and true, any pattern will be thrown out of line. Take one length around a corner so that it overlaps by about 50mm (2in) and make a series of diagonal snips at the edge so they stick smoothly to the wall. Hang the next length covering the snipped edge and lined up with the wall edge.