I get ideas from wallpaper books. I use Illy for this work as it is much better at tiling than Xara as you can save your pattern as a vector brush. The normal way that I do it is to work out my flourished pattern using the pen tool and then use a square with no fill or stroke and use it as a mask or Object -> path -> divide objects below command. Then drag to either to the swatches or brush palettes. The advantage of using Illustrator over Xara here there are so many ways that you can use simple shapes and patterns it can be a brush, a symbol, a fill warp (mould) and all can be expanded as they are still vector.