Lets do a quick list:

• Introduce main character for the episode.
• Show main character's situation/tormentor/person who annoys them.
• A name is submitted and accepted.
• Hell Girl shows up, give the deal and the price and leaves the doll.
• Main episode character has angst about going to hell/sending someone to hell/jelly donuts are fattening.
• Foe either prompts the main character to send them to hell or the main character gets bored and does it or maybe the string slips.
• Foe goes to hell.

Lather, rinse, repeat this for 7 episodes.  Seriously, you can watch one of the first 7 and skip directly to episode 8 and not miss a thing.  In episode 8 we are introduced to the two regularly reoccuring characters, peeping tom journalist guy and his daughter loli-girl.Journalist guy is down on his luck and basically survives by taking pictures of naughty married folk doing bad things and selling it back to them to keep it quiet.  He accidentally stumbles upon the legend of Hell Girl and starts trying to stop each of her customers/victims from exacting revenge because he believes it to be a bad thing.  Loligirl meets Hell Girl in the street and suddenly becomes a direct avenue into the inner workings of running Hell Girl Inc.  She has visions of the events before they happen.  At this point we see a change in the plot:

• Introduce main character for the episode.
• Show main character's situation/tormentor/person who annoys them.
• Loligirl has a vision or Journalist stumbles upon the epsiodes story.
  
• A name is submitted and accepted.
• Hell Girl shows up, give the deal and the price and leaves the doll.
• Main episode character has angst about going to hell/sending someone to hell/jelly donuts are fattening.
• Journalist tries to intercede and stop the main character from sending someone to hell.
  
• Foe either prompts the main character to send them to hell or the maincharacter gets bored and does it or maybe the string slips.
• Journalist shows up too late to stop it.
  
• Foe goes to hell.
• Journalist and Loligirl feel bad (although Loligirl secretly believes that Hell Girl is a good thing).
  

This goes on until around episode 19.  You could probably watch one or two of these episodes and skip right to 20 because that's where things get somewhat interesting as an esper/hell boy appears and challenges Hell Girl to a duel.  From here on out things change and we get a glimpse into why Peeping Tom Journalist guy hates the very idea of revenge and how Hell Girl came to be.  Finally conflict and resolution beyond the episodic scale.

So basically, watch 1-3 episodes from the first group of 7, episode 8 and 1-2 of the others from the second group and skip to 20.  Then go ahead and watch the remaining.  In that way, the show is pretty decent.  I know the pacing and length were deliberate but in my own opinion it was way too long and almost painful to sit through.  Like ROD The TV it probably could have been a 13 episode series and been much, much better or at least less likely to place high in the I'd Rather Eat My Own Feet Than Watch This Longwinded Crap contest.  All right, I jest.  It isn't that bad, really.

(images courtesy of lolitron.org because I had already removed this series from my hard drive)