When a pattern includes an S shaped curve that is worked with evenly spaced stitches along its length it is hard to visualise. The section where the curve changes from an inside curve to an outside curve is the tricky part.
Once you realise how it works it is just a matter of continuing the stitching and the shape will form itself. However, if you try to analyse it in advance you may find it confusing.
The stitching diagram is from the lily greeting card sewing pattern sold on the Stitching Cards web site. At first glance it may look difficult so some of the lines have been drawn in different colours. This should help you see where they are going at the crossing point.
If you work in a methodical way the shape will form itself.. Ensure that you move forward one set of holes at a time. Keep the same number of holes between the hole you come out of and the hole you go in at. In this example all the stitches are 10 holes long. Many of the holes are used twice. Continue the stitching until the shape is completed.