I typically just light the top until it's all glowing red, then tamp it down after the initial "fluff up". If it goes out, then charring light complete, I just light again until I see a nice, even glow from the tobacco and usually I'm set.
Unless it's a flake, then I pull out the blow torch, hold it there for 5 minutes, then it likely still isn't lit, prompting another 10 minute light, then I might be good to go for about 5 minutes. That is, if it's folded. Then again, I'm still working on my flake procedure. I think I'll need a new tin of ODF soon to keep working at it. When I rub it out, no issues whatsoever.