Rooms are full of obstacles: doors, radiators, windows, chimneybreasts and corners. When you approach an external corner - an edge that sticks outwards into the room - simply hang the nearest drop, then paste, fold and hang the corner piece so that an overlap of paper wraps smoothly around the corner by about 50mm (2in). To avoid bubbles and creases, nip diagonal cuts in the edge and smooth them flat with a paperhanger's brush. The next drop of wallpaper is hung overlapping and covering the 'snips'. If you are using a vinyl wallpaper, you will need to use an overlap adhesive so that the paper sticks to itself on the overlap.

Working Around a Corner

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.

Doors

1 Hang the last full drop

When you come to a door, hang the last full drop of paper up to but not over the door, smoothing it down from top to bottom with a paperhangers' brush to remove air bubbles.

2 Hang the second length

Paste the next length of paper - but do not apply paste to the area of paper that will be cut away to allow for the door. Hang this length of paper and allow the unpasted area to fall loosely over the door. Cut the paper leaving a 50mm (2in) overlap at the top.

3 Trim at the side

Press down on the top corner of the doorframe to make an indentation in the paper. Cut diagonally from the edge of the paper at 45 degrees to this indentation. Brush the wallpaper into the angle between the wall and the doorframe and then trim excess paper.

4 Over the door

Using the unpasted piece of wallpaper, which hung over the door in step 2, cut, paste and hang the short drop from the ceiling or cornice down to the top of the door frame. Repeat steps 2 and 3 on the other side of the door frame.

Windows

If a window is wide enough, hang one drop centrally over the top. If it is not, drop a plumb line to one side of the window, about 120mm (5in) less than the width of the wallpaper, so that the first drop of wallpaper overhangs the window frame. Paste and hang the paper so that it lies loosely over one edge of the window frame. Using the paperhanger's brush, gently brush the paper into the angle between the wall and the window frame to crease it. Carefully peel the paper back and then cut along the creased line and brush the wallpaper back into position. Alternatively, you can leave the creased paper in place and trim it using a craft knife, leaving the paper in place in the angle and running the knife along the crease. Use a seam roller to press it down, if necessary.

Stairs

Wallpapering a staircase is not as difficult as you might think because the paper is measured, cut, pasted, folded and hung as for any other surface. The difficulty lies in gaining access to considerable heights, so the main thing with this job is that you can reach safely. Never lean over the balustrade to reach walls: hire adjustable ladders specially designed for staircases. A safe, sturdy working base will have its rewards in smoothly hung paper with closely butted edges and accurately trimmed top edges.

1 Identify the longest drop

The first drop of wallpaper you make on a staircase should be the longest. Drop a plumb line and then mark an accurate vertical line on the wall. This will act as the guideline for hanging this and subsequent lengths of wallpaper. Mark the wall with a pencil at intervals down the plumb line then join up the marks with a straight edge to make the vertical guideline. To ensure it is accurate, make a plumb line long enought to hang the entire length of the stairwell.

2 Position the first length

Take your time when you position this first length to make sure that it is vertically true as it will be difficult to correct mistakes later on. Never use the wall as your guide - even in modern homes, they are rarely straight. Instead, always refer to the plumbed line. Paste and hang the first drop to the left of the drawn line, smooth out any air bubbles with a paperhanger's brush and trim off excess. Hang the second drop, butting the edges tightly together.

Light Fittings

Whenever you paint or wallpaper around a light switch or electrical socket, you must always switch off the power at the mains, and identify and remove the fuse for that circuit.

Wallpapering around obstacles such as these requires a steady hand and a great deal of patience: don't rush, otherwise you will spoil the effect. After all, it's these little details that make the difference to a professional finish. There are two ways of making wallpaper 'fit around' switches: you can either remove the faceplate of the switch - but only after the power is switched off - which makes working easier, or, if you prefer, you can very carefully cut around the switch or socket. Use decorator's scissors and make sure the blades are kept free of paste.

1 Loosely hang the drop of paper

When you arrive at a switch or socket, loosely hang the drop of wallpaper on the wall. Using a paperhangers' brush gently press the wallpaper against the switch or socket to make an impression - but not a hole - in the wallpaper. Carefully cut a 'star' by making four small diagonal cuts from the centre to the corners.

2 Trim away excess

Fold back the four pointed triangles pressing their edges into the angle between the wall and the switch. If you take the faceplate off the switch or socket, you can smooth the cut edges and replace the faceplate to hide them. Alternatively, carefully trim away the excess with scissors or a craft knife and brush the paper's edges into the angle.

Radiators

The best way to wallpaper behind a central heating radiator is to remove it from the wall completely but, if this is not possible, switch off the radiator and let it cool down. Measure and hang a full drop of paper, but brush down the top half of the paper on the wall only, allowing the bottom end to fall loosely. Next, carefully pull the lower part of the paper away from the wall and trim it to fit behind the radiator.

Make two creases or marks in the paper indicating the location of the radiator wall brackets. Cut upwards through the paper to these marks. Lower the pasted paper behind the radiator so that it passes on either side of the bracket. To smooth the wallpaper into place, use a long stick with a well padded end - several old clean 'T'-shirts tied to the end work well - or a clean, dry crevice or radiator roller with an angled handle.

If you can't manage to get behind the radiator, you will have to trim off the drop - leave about 150-225mm (6-9in) extra length that you can tuck behind the accessible top part of the radiator. At the bottom, where the wall is visible, 'patch' with paper that matches the pattern at the base of complete drops on the walls to the sides of the radiators.

Working Around Radiators

If you can't remove your radiator from the wall, trim the wallpaper so that you can tuck a length behind it.