You have to expand rapidly at the start for this to be useful, but I found the Poger blood strategy useful:
http://www.shrapnelgames.com/cgi-bin...4;t=000269;p=3
Just choose a sacrificial province of 5k+ (ideally 10k; I don't know exactly how population affects things, but 10k seems to be a good number). Mass produce scouts (20 gold, almost no resources) in every province that has them. Set the tax rate to zero, and have them all slave there... research construction up to level 4, and once you get 50 slaves (with 16 scouts, should take about 4 turns) empower a scout in blood, and have him start making Sanguine Dousing Rods. Every 50 slaves, empower anther scout and give him a rod... with maybe 4 scouts with rods and 12 without, you'll get a nice income.
Don't start this process too soon! Wait until you can sacrifice the blood province's gold income without hurting your ability to build a conventional army or recruit mages.
The first unit you empower in blood might be a national mage - that way, you get cross-path spells and constructions, like crossbreeding and the blood stone (or something like that, Earth and Blood).