John,
There are many ways to skin the cat, but one must take inconsideration where and when to warm? In the old days we popped a roll of Kodak E100SW (SW stood for Saturated Warm) or if we shot negs, an 81A filter.
Today we have many options. My favorite for digital, which is the way I shoot all my glamour and people shots, I set my cameras at the white-balance of 6000K, this fools the camera into thinking the light of the scene is cool, thus adding some nice natural warmth. I use this indoors and outdoors, sunset to sunrise.
Another option, that can be combined with the above, if you're shooting a sunset, place a Rosco #02 Bastard Amber in front of your light source, point it at the subject. This can be a beauty dish, soft box, grid, etc., any light source, I even do this with my Hensel Ringflash and Sunhaze attachment.
Still another option, especially if you're not shooting a sunset, place a Rosco 3/4 CTO (Continuous Temperature Orange) gell in front of your electronic flash, then set your white-balance at 3200K. What the 3/4 CTO does is convert flash (5500K) to tungsten (3200K). By white-balancing to tungsten, especially when shooting outdoors, you'll get more blue in areas where the flash doesn't hit--outdoors this will make your sky go dramatic, like a polarizer.
Still other options, place 1/8 or 1/4 CTO's in your softbox or in front of your light or light modifier. The last option, the Rosco "Straw" gel works great too.
On the Bastard Amber, that gel is designed to mimic "sunset light" so I use it for sunsets more than anything. I hope that helps, wishing you the best, rg sends!
(my kids in San Antonio, Hensel Ringflash with a 3/4 CTO)

(April 2006 Playboy Playmate Holley Dorrough, Virgin Islands, Hensel Ringflash w/Sunhaze w/Bastard Amber in housing, white-balance 6000K)
