Ice, compression, elevation when you get home from work. At work, take one of those snap cold packs with you and put it on your ankle, five-10 minutes per side (not directly on your skin, though - just on your sock should be fine) or if it's big enough, around your ankle, during your break. This helps enormously.
Also, if you're standing in one spot on concrete or other hard surface, you should look into special mats (I forget what they're called). I've heard from folks who use them that they are beneficial for feet and back if one is required to stand more or less in one spot for long periods of time.
If you're walking around a lot, make sure you have good arch supports inside your shoes, and that, if you have the same problem I do (that is, a tendency to walk on the outside of your foot) that wears down the outside heel of your shoe, BUY NEW SHOES or get them repaired if they are reparable. Mine usually last for about 3 months before I have to get another pair (I walk just about everywhere); using them any longer results in nasty tendonitis (as I've been having lately, for just that reason as well as weight issues).