Dragons:
The biggest mistakes made with this strategy are not making enough drags and not using the right spells.
Bring ALL dragons to your war attacks! I cook all lvl3 dragons and request max balloons or another dragon in my CC from the clan. That’s a total of 11 lvl3 dragons. No other troops should be cooked. I bring 3 rage spells and 1 heal spell but you can also mix it up by brining 2 rage and 2 heal. If you have only 3 spells you should bring all rage, or 2 rage, 1 heal. You should only bring 3 lightning spells vs a TH7. There is no need to lure out enemy CC with this strategy.
I start by finding the side of the base closest to the town hall (TH). This ensures I will get a 2-star if the dragons act drunk and don't stay together. Sometimes it’s best to drop a dragon on each corner to clear out some of the side buildings to ensure the main mob of dragons focuses on the middle of the base when released.
Deploy the dragons in a line (not bunched up holding your finger down on one spot) while also dropping CC for the 11th dragon or max balloons. Once the dragons start destroying I drop rage spells (2) to move that whole line of drags halfway through the base, hopefully killing TH and causing over 50% damage (2-star). If your dragons make it to the TH but look like they may be taking too much damage then drop the heal spell to be sure the TH his killed. Now wait for them to move about ¾ of the way through the base and drop the last rage spell. Again, if you are at TH8 you will use a similar tactic but with 2 rage and 1 heal or all rage spells.
Always consider where the TH is and where the air defense (AD) is when using dragons. I see too many people appearing to choose a random starting location. The idea is to take out as much air defense as you can with the mob and first 2 rage spells and get the TH killed for the sure 2-star and likely a 3-star if spells are used properly and dragons aren’t distracted by heros, skeleton traps, etc.