This army composition is for CC6+ players. Your command center has to be level 6 because you will need repair ships for this strategy. This strategy will be able to take out pretty much any CC6 base. You need the following units for this strategy:
1-2 Repair Ships
5+ C4 Roaches
It is recommended to have a level 2 command ship, as the healing perk can be useful using this strategy.
Destroying the missile turret is the most important thing to do, as they will take out repair ships with ease.
First, you should clear any surrounding structures. Then, lure out the squad hq troops and kill them using hawks. Drop 1-2 storms close to the missile turret. Release 2-3 C4 roaches to break open a wall. Send in all but 1 of your storms, as it might come in handy later, such as for distracting a certain defense for just a moment. After sending in your storms, drop hawks/raptors behind them to help take out defenses and other buildings. You might need a healing perk to keep your storms alive as they take out the missile turret. Once it is down, drop 1 of your repair ships, then the second one. Try not to drop them close to the missile turret, as good players will have placed their ballistic missiles close to it. After these steps, there is pretty much nothing to do, as your storms will slowly destroy the opponent's base while your repair ships heal them.