I've had this problem ever since I started. I'm constantly refining my technique, but here's where I'm at now.
1) Dry baccy.
2) Three-step pack. And a little tighter than I first thought. Loose packing is a more pervasive problem than tight packing, I'd wager.
3) Tamping is a bad word. First of all, I used to do it too much, and second of all, I used to do it too 'heavy'. I've started Grinding instead--grind the ash at the top of the pack in a circular motion, into a fine powder, but without upsetting the delicate structure of the baccy underneath. This is crucial because...
4)...ash dump. I do this with nearly every relight now, and I relight a lot less as a consequence. If you're doing it right, the only thing that should fall out of the bowl is the fine powdered ash. Use a gentle tap on the back of the bowl with your finger as an incentive.
5) When you get to the bottom of the bowl and this method starts to fail, just dump whatevers left. I routinely dump about 5 to 10 percent of what I pack. The effort it requires to keep that stuff lit is way more trouble than its worth.
and finally,
6) Stop listening to me! I've only been at this a year, what the hell do I know?! That being said, this has helped me alot. And I learned it all here.
- Josh