What he means is that you can barch all the way to masters by simply targeting bases that have more buildings outside than inside.
Here's a tip...
Train up 3 lightning bolts (minimum level 4). Go with 100 barbs, 100 archers, or 80 barbs, 120 archers...you'll get a feel for how many you need depending on your comfort level. Make sure you have a full cc and at least your barbarian king available.
Target support buildings, army camps, collectors, labs etc...and look for bases where these structures are on the outside well out of reach of the defending clan castle and heroes. For TH9 bases you need to destroy about 36 structures to get 50% (depends on how many builder huts they have), for th10 bases, you need to destroy about 40.
Keep the lightning bolts handy to do one of two things.
1) take out a mortar that's defending a lot of percentage points
2) use a single lightning bolt to take out either a barbarian, aq altar, or one of the builder huts tucked away inside. One bolt is enough to take out those buildings.
3) use your cc and / or your barb king as a last resort to get you to 50%.
A derivative of this strategy uses 3 or 4 hog riders late into the raid and specifically to tank splash defenses for archers.
Don't spam troops...deploy with a purpose because every troop will count. Of course always look for the snipe but never ever take on a base without a full army (a lot of people like to trap their bases for easy trophies, (4 level 8 teslas, = 400dps at an extremely high rate of fire).
I did my run to Masters as a town hall 8 but with hogs before the giant bomb buff. It was a little silly dumping 1k's worth of dark elixir troops to take down one damn building, but at the time, desperate times called for desperate measures.
At th9 - going to masters is a walk in the park...you can barch, balloon, hog, whatever you want, it's just a question of how much time you want to put it into.
Best of luck with your push.
https://www.youtube.com/watch?v=zXSyxYhwl-g