Before you start to bake, it is good to know the difference between all-purpose flour, cake flour, bread flour and self- raising flour. To make it easier you should start this by knowing a little bit about GLUTEN.

Gluten is a special type of protein that is commonly found in wheat, rye and barley. Gluten helps to make bread elastic and provides it with the chewy texture when eaten, but mainly gluten keeps the gases that are realesed during fermentation in the dough so the bread is able to rise before it is baked. Gluten also firms up when it is cooked and with the help of starch, its ensure the bread maintains its proper shape.

In USA :

All-purpose flour comes in two basic forms-bleached and unbleached-that can be used interchangeably. Flour can be bleached either naturally, as it ages, or chemically.

Cake or pastry flour is a fine-textured, soft-wheat flour with a high starch content. It makes particularly tender cakes and pastries.

Self-raising flour is an all-purpose flour to which baking powder and salt have been added.

Cornstarch
This is a refined starch that comes from corn. It is mostly used as a clear thickening agent for puddings, fruit sauces and Asian cooking. It is also used in combination with other flours for baking.

The choice of flours for home cooking and baking in UK

Plain Flour - also known as all-purpose. Use for shortcrust pastry, sauces and gravies where a raising agent is not required.
Self-raising - Flour to which a raising agent has been evenly mixed. Use for cakes, scones and puddings.
Soft Flour - a soft white flour which has been milled very finely to give sponges, cake and scones a higher rise and finer texture.
Strong Flour - a flour with a high protein content providing a high volume and open texture. Ideal for bread and all types of yeast cookery, Yorkshire puddings and puff pastry
Wholemeal - 100% extraction, made from the wholewheat grain with nothing added or taken away.
Brown - usually contains about 85% of the original grain. Some bran and germ have been removed.
White - usually 75% of the wheatgrain. Most of the bran and wheatgerm have been removed before milling.
Wheatgerm - white or brown flour with at least 10% added wheatgerm.
Malted wheatgrain - brown or wholemeal flour with added malted grains.
Stoneground - wholemeal flour ground in traditional way, between 2 stones. (This info is taking from "fab" Flour Advisery Bureau)http://www.fabflour.co.uk/content/1/25/types-of-flour.htm