I bought the cardboard letter from a craft shop (I'm not clever enough to have made it!)to make this for my friends' daughter. I'm hoping it's going to look good in her nursery.
I took an old fashion magazine and cut out squares of colour and pattern. I then pasted the bits on with slightly watered-down PVA glue and an old paint brush. It was a bit fiddly to get them to bend over edges and avoid bumps, but I got there in the end.
After the whole letter was covered, I brushed it with a few extra coats of pva which dries clear. Et voila!