Oily skin is a result of excessive production of sebum which is an oily substance naturally produced by skin. The excess leads to clogging of skin pores, accumulation of dead cells and formation of pimples or acne.
The major purpose of oily skin care is to remove the excessive sebum. This is not everything that oily skin care is about, but a big part of it.
Oily skin care starts with the use of a cleanser – not all cleansers will work. You need a cleanser with salicylic acid that retards the rate of sebum production. Cleansing should be done twice a day (or more in hot and humid conditions).
Most of the oily skin care products are oil-free, but in any case you need to check the ingredients before buying any product. The oily skin care routine can include an alcohol based toner, but this is only for extremely oily skin. This can be the second step in your oily skin care routine, but remember that excessive toning can harm your skin.
The next step in your oily skin care routine is a mild moisturiser. The degree of oiliness of your skin will determine whether you need to include this in your oily skin care routine. In any case a moisturiser must be oil-free, wax-free and lipid-free.
Also use a clay mask as an oily skin care measure.
And as always, it is great to consult a competent dermatologist.