One thing I tried which helped decrease oil production was to use a mud/clay mask every other day or weekly depending on the weather since doing this too often can dry out your skin. I use either St. Ive's or Queen Helene's Mint Julep mask (any brand that has kaolin clay in it would work) and leave it on for 15 - 30 mins (sometimes more if I forget) then use a sponge or soft face towel soaked in warm water to take it off. I follow this with a mild face wash, then witch hazel applied with a cotton ball, and whichever moisturizer I'm using at the time (sometimes I just use the Aloe Vera Gel from Jason). I do this before going to bed, and in the morning, I just use witch hazel then an oil-free moisturizer before going to work.
If you don't want to use a clay/mud mask, I find that applying Witch Hazel toner/astringent after cleansing works really well on its own. I use T.N. Dickinson's (you can get witch hazel at the chemist / drug store). I also carry facial tissues to blot excess oil throughout the day -- you know the table napkins they have at Starbuck's? Tissues similar to that work the best. They're even more effective at blotting oil than the more expensive blotting papers sold for that purpose (I used to use the tea tree blotting papers from The Body Shop, which worked great but were expensive).
Also, since hormones are the root cause of excessive sebum production, I try not to get too stressed out during the day (which is really hard to do!) and stick to a healthier diet (lots of vegetables, no soda of any kind, tea w/o sugar is my drink of choice). I actually did an experiment and started eating fried chicken again after avoiding it for about a year.... sure enough, my skin became a lot oilier and I started breaking out a week after
, When I stopped eating fried food, skin went back to normal.