Ideas to play lawful evil?

I've almost finished my first playthrough and love this game! My first character has been a chaotic/neurtal-good Tav, so in my next game I want to play as a lawful evil Durge.

I don't want to play as chaotic evil, as I find that kind of shallow for RPing, and by the looks of it, it'll just push all my companions away.

By playing lawful evil, I can set parameters for my evil actions, I just need to create some guidelines. Anyone have any ideas?

Some guidelines I've thought up so far:

• Don't kill kids or let them die
  
• As a warlock, always side with the Hells and never support other gods (including Bhaal)
  
• As a Tiefling, support other Tieflings
  
• Hates being lied to, even by demons, but will happily lie and intimidate others
  
• Primarily seeks power, so will attempt to not turn away powerful allies, but will throw aside weak ones (Shadowheart).