Pure cotton would be the fabric of choice for your first project , mixed fibre cloth can tend to make the pleats pop out . Gingham is often used by beginners as it is possible to follow the line of checks.
Finer fabrics pleat up more tightly than heavier fabrics and one must therefore allow more width for the smocked area..
A plain fabric will show up detailed smocking easily whilst a patterned fabric may need stronger smocking to be effective .
Take some time to distribute the pleats evenly before you begin smocking . This can be done by pulling the threads up tightly to get them neat and then releasing them to about 2/3rds of the required width.
Remember that the main object of smocking is to connect the pleats together with your embroidery stitches, so it is important to stitch into each and every pleat .
It is important to use a new needle for all your projects - a No 7 crewel is recommended , as the point will dull with use and can split the thread.
Try to get into a rhythm with your stitches , this helps to keep your tension even , although practice is the only way to find the right tension for your work.
It is a good idea to make a few practice samplers before beginning your first project. This will give a good idea of the correct tension, thickness of thread and colour combination for your garment.
Always start your smocking on the second row of gathers , as the top row can be used as a guide for completing the garment.
However tempting it may be it is best not to 'pop' any of the tacking threads until you have completed all the smocking.