To start the discussion on oily skin care, its imperative to first understand the cause behind oily skin. Put simply, oily skin is a result of excessive production of sebum (an oily substance that is naturally produced by skin). As is known to everyone, excess of everything is bad; so excessive sebum is bad too. It leads to clogging of skin pores, resulting in accumulation of dead cells and hence formation of pimples/acne. Moreover, oily skin spoils your looks too. So, oily skin care is as important as the skin care for other types of skin.
The basic aim of oily skin care is the removal of excessive sebum or oil from the skin. However, oily skin care procedures should not lead to complete removal of oil. Oily skin care starts with the use of a cleanser. However, not all cleansers will work. You need a cleanser which contains salicylic acid i.e. a beta-hydroxy acid that retards the rate of sebum production. Cleansing should be done twice a day (and even more in hot and humid conditions).
Most of the oily skin care products are oil-free; however, it is always good to check the ingredients of the product, before you actually buy it. This is especially important if a product is marked as suitable for all skin types, instead of oily skin care product. Oily skin care is also dependent on the degree of oiliness, if you arent too oily, so some of these suitable for all- type of products might be work for you too. For extremely oily skin, only oily skin care products are suitable. Your oily skin care routine can include an alcohol based toner (for an extremely oily skin). This can be the second step in your oily skin care routine i.e. just after cleansing. However, excessive toning can harm your skin.
The next step in your oily skin care routine can be a mild moisturiser. Again, the degree of oiliness of your skin will determine whether you need to include this in your oily skin care routine. If you do decide to include a moisturiser, be sure to use one that is oil-free, wax-free and lipid-free.
You could also use a clay mask (say once a week) as an oily skin care measure.
As far as the oily skin care products go, you might need to try out a few before you arrive at the one that is really suitable for your skin.
In case these measures dont give you the desired result, consult a good dermatologist for advice. He could prescribe stronger oily skin care products like vitamin A creams, retinoids, sulphur creams etc , which can help counter the problems of oily skin.