Start by finding a base with full or nearly full Dark Elixir Drills, at at least level 3.
When you have found one, it doesn't matter whether the drill is in the core, if it is only one in the core
If one of the drills are in the core of the base, drop as many lightning spells as you want, just keep in mind that with level 1 lightning spells, that 3 of them will leave a level 3 Dark Elixir drill alive with 20 hit points (assuming that all of the lightning strikes hit)
Once you zapped the one in the core, there is most likely one that is surrounded with one layer of walls (if it is a TH8 you're raiding). This is where you send out the barbarians in a wave pattern to take out the distracting buildings outside the walls and also to tank for the archers
After all or most of the distracting buildings are gone, drop down the archers in a wave pattern, some will target buildings other than the drill, but that's fine because you are doing this so they don't all die from 1 mortar strike.
(No execution notes)
Keep archers in a 2:1 ratio if you have more space, for example, with 200 space, you would have 133 archers and 67 barbarians, this attack is for farming Dark Elixir or gold. While I was using this attack at TH7-8, I found that there is an overabundance of DE in Silver II league in particular, so I would stay there.