For combination skin with acne, you want to make sure you use oil-free products that will treat the acne, but still hydrate and normalize your skin. I recommend Origins Zero-Oil Moisture Lotion, which is a nice light-weight daytime moisturizer that contains natural acne-fighting ingredients to treat acne all day long and keep skin hydrated.
Over the lotion, I suggest applying a treatment to seal your skin from the elements and lock in moisture. Try Clarins Lotus Oil. Might sound strange to use an oil on top of an oil-free lotion, but this combo actually works very well to improve your skin's condition and prevent skin from over-producing its own oils, which causes breakouts. This oil was formulated for acne sufferers, so it will not sink into pores and congest your skin, like some other face oils.
It is also very important to keep acne-prone skin exfoliated as much as possible. Everybody's skin is constantly shedding dead cells, which end up settling on the surface of your skin and can prevent products from sinking in and taking effect. When skin is acne-prone, the dead skin cells that sit on the surface are usually full of acne-causing bacteria. So if you are not doing anything to rid your skin of these dead cells, they will only congest skin further and re-deposit bacteria into your pores, making acne worse. Try Mario Badescu Glycolic Acid Toner. I use this everyday after cleansing, and it really keeps any problem areas at bay. Glycolic acid keeps skin clear and exfoliated, smooths rough textures, cleans out pores, and promotes cell-turnover, creating healthier skin over time.