+pump after every feed
+pump more often at work
+eat well, drink plenty, get enough sleep
+relax
+spend a weekend relactating (do nothing but feed, sleep and be waited on by your other half)
(my own oddity:) wear breastshells all the time
+LOTS of water - keep a large bottle full by your desk, and take sips frequently. Be sure to at least try to get enough sleep.
+Brewer's Yeast tablets (easier to find than Fennugreek or Mother's Milk tea, at least around here anyway). If you are truly desparate, ask your physician for a prescription for Reglan/Maxaran (same stuff, different names). It is a gastro-intestional drug that happens to have a side-effect of boosting production in lactating women. If your GI tract is fine, it won't cause any problems there and it is harmless to infants (in fact, it is one of the drugs used to combat reflux in infants). This is not a permanent fix but can be used to boost production for women trying to relactate or after a stressful period has depleted your supply.
+Fenugreek capsules &/or mother's milk tea -- I have found them very useful. Take two with each meal and two before bed.
I take 3 tablets at lunchtime (I use a local preparation which doesn't have gelatin capsules). That's 1800 mg. For our Canadian members - it is HSC, distributed by Vita Health. If I'm trying to increase my supply rather than maintain it, I take the same amount in the morning, as well.
herbs: blessed thistle & fenugreek (both in mother's milk tea, also available at hfs)
The recipe for Tiger's Milk is as follows:
       1/2 cup frozen undiluted orange juice (or any fresh fruit,
               a couple of bananas, peaches, blueberries,
               strawberries)
       1 cup fresh skim milk
       1-2 teaspoons vanilla extract
       1-3 teaspoons Safflower Oil

       Blend all the above in a blender. Add: 3/4 cup instant
       powdered skim milk, 1/4 - 1/2 cup Brewer's Yeast (may want
       to start low and build-up STRONG TASTE). Stir in 2-3 cups skim
       milk. Drink at least 1/2 cup at a time, at least 4 times a day
       (Brewer's Yeast is available at health food and natural stores.
       Also some pharmacies and grocery stores)