Recommending a particular strategy is hard, because there isn't really a single META attack strategy at TH13. You have a lot of options which are good against certain bases and not very good against others, and other options that will always get you two stars on your attacks when executed properly but often don't go the distance for 3, etc, etc.

At TH13 doing attacks in stages gets even more important - this somewhat starts at TH11 where dropping some troops early will get some damage in before the eagle artillery starts wailing on you, but picks up at TH13 now that the town hall is even stronger with inferno beams and drops a more explosive bomb wjen it dies. You either need to use your warden ability to counter this bomb, or not funnel all your troops straight into the town hall.

Running a side attack while defenses are distracted by the main attack or by a tank starts getting more important too. Scattershots can completely wreck certain armies, and it makes a lot of sense to distract their attention away from certain group of troops while they're approaching. Yeah yeah, you can use a freeze spell for this too or use an invisibility spell, but if you have the troop space in your army, you'll save an all important spell slot for something else more useful - maybe freezing an inferno or having space to use a rage or jump or clone or poison spell or something. For this reason, the old rule of "Never mix ground and air troops" starts to break down as well - if you can distract all the high damage splash defenses with one kind of troop, the other can zoom in untouched.

Here's some more specific ideas against a few kinds of bases:

• Ring bases - you'll know a ring base when you see it. The inner core always has the town hall, and probably an eagle artillery too. Dragbats can pick these apart, especially if the infernos are set on single target mode. Often the wizard towers and maybe even the scattershots are on a more outer ring. Drop the dragons early - then drop the bats on one side or the other (not both) of that group so they go around the ring in a clump. Use balloons to distract the wizard towers or Scattershots as the bats are approaching them.

• Town Hall and Eagle Artillery in opposite corners - A lot of times you can use a super queen attack with healers on these. Drop the queen and the healers on the corner with the Eagle Artillery - not the side with the town hall. Use some giants and bowlers and wizards and wall breakers as needed to funnel for the siren and path her towards the Eagle Artillery. Once that's gone, drop your main attack to either the right or left side of the Eagle Artillery - since the archer queen took that corner out, everything will path towards the middle and towards the far corner with the town hall. Mass witch attacks are reasonably easy to execute with these, although you can use lots of other comps here too - in witch attacks it helps to take either one or two sets of 4 earthquake spells, and maybe even a wall wrecker too, just to make sure you hit the town hall on the other side. Something I've seen a lot with these kinds of bases is to add an extra stage at the beginning where you drop a battle blimp with super wizards inside on the corner with the eagle artillery, get the wizards dropped in the middle of the base, use spells to make them invisible and rage them, and then do your super queen stuff - if the middle of the base is gone the rest of your army will stay together going to the town hall, and then you just use the GW ability to counteract the bomb.

Yetis and bats for ring bases, hybrid for everything else