I use a combination of hardwood logs and lump hardwood charcoal (not charcoal briquettes). The charcoal provides fast, high heat, and the smoking wood burns more slowly and adds aroma and flavor. Look for natural lump charcoal in hardware and gourmet stores. You can order lump hardwood charcoal and hardwood chunks by mail from Nature's Own Chunk Charwood (www.char-wood.com) in Rhode Island.
Arrange the wood and coals in an even layer, and don't touch them once they're lit. Every time you mess with the fire, you alter its integrity, disrupting the flow of oxygen and knocking calories out of the system. For this reason, I don't recommend the traditional method of stacking the coals, igniting them, and then spreading them out. This pyramid method also hinders you from getting a range of temperatures.
The coals should cover an area that's at least a few inches larger than all the steaks you'll cook at one time. The grill grate should sit three to four inches above the coals.
To judge when the fire is ready, look at the coals and use the hand test. When the flames subside and the charcoal glows red with some ash starting to appear, the fire is hot enough for rib-eye and flank steak. At that point, you should be able to hold your hand a few inches above the grate for one second. Shortly thereafter, the embers will be completely covered in ash, a sign that they're losing heat. That's medium high—perfect for a thick porterhouse.
It's fine to season the meat with herbs or spices up to an hour before grilling, but don't salt them until the last minute. Salt draws out moisture and will dry out the steaks if added too soon. Before putting the steaks on the fire, bring them to room temperature and rub oil on the grill grate.