Different skin types
Oily skin
Oily skin is skin that overproduces oil and can cause acne and can clog up pores, the main focus would be not to strip the skin of its oil but rather use products which are nourishing but doesnt contain any oil.
Combination skin
Combination skin is skin that has some areas which overproduce oil and other areas where it doesnt produce enough so it has some dry patches and some ooily parts, this type is a bit difficult to deal with and may need different products on certain areas.
Dry skin
With dry skin the most important thing to keep in mind is moisture, your skin is obviously not producing enough oil to keep your skin hydrated so you must use certain products to add that bounce back.