If you want the easiest way to reach Masters as a TH8...
it will cost you some gold and some time...
The troop composition that I used to get to Master at TH8 were 8 Giants (Level 4), 12 Wall Breakers (Level 4), 8 Hog Riders (Level 4), 10 Minions (Level 2) and the rest split between Barbarians and Archers (Level 5) & Level 4 Rage Spell.
1. Try to find exposed TH for easy trophies with minimal troop usage (2 level 5 archers can take out any level TH). Watch out for hidden teslas. If they pop up, drop the giants and hogs to absorb the attack and barch the TH. I used minions for the exposed TH that had a mortar near by.
2. Search to find TH behind one wall. Again send in the least troops possible to destroy the TH. If all troops are needed the order to drop would be giants, hogs, wall breakers, barbs, archers then rage the barbs and archers to take out TH.
This method was the fastest & cheapest method to get to Masters and collect gems. The reason this worked well is because it's a fast troop build time which allowed me to string attacks back to back without letting someone attack me. The last 100 trophies to reach Masters is brutal.
Good Luck!
or you can just spend gold and TH Snipe lol...