On attacks, it seems to be best, if possible, to choose the attack based upon their D.
I've made way too many "with whatever I had", and, it DOES make a huge difference.
Also, the places you choose to deploy and the timing seems to make a huge difference.
As the bases get tougher, variables such as what they did as far as their traps and arranging the D for cover fire, etc...can turn what looks like a slam dunk into a death trap.
Basically, when I look at a base to attack, I try to see if they are geared more to protect against AIR or Ground.
For example, if they have bows, are they set to G or A? Do they have towers covering the mortars and cannons/visa versa?
If you can take out a KEY cover, say air D, would it leave your balloons. minions or drags free to frolic?
Is there a "Path of Least Resistance" to their TH? What D covers that box you need to get to and through? Do you need wall breakers?
Should you gallop some hogs in to take out the air cover and then dragloon them? Does it look like there are larger open areas that are likely to have hog bombs/Teslas/air mines? Can you send ONE recon troop in to blow / trigger them before they take out your whole pack?
Where does their castle circle cover?
Can you draw out their troops and kill them outside the base with lightening/your troops? Their royals and castle can be a PITA otherwise.
If you draw their castle troops, and its all barbs or hogs, etc...they can't shoot UP, so an air attack is not concerned with them....but your royals might, etc.
If they have a drag or wiz/archers, etc...you need to take them out before sending in waves of fodder for them.
Where does their royal patrol go? An air attack over their King is great, he walks around clueless and doesn't bother you, but queenie's arrows are a real threat...but, are single target, so a mass of spread out wee targets or tough enough troop (PEKA, Drag, etc), can take her out...but a combo is typically more successful...because YOUR attacking troops may decide to slash the crap out of a builder's hut while she shoots them....etc.
On the timing....some troops just go around the perimeter, and you can't count on them to even go through a hole if you make one to the inside, so, if you can, you want to disable whatever defensive fire would be pounding your guys as they meander about. So, if you release say balloons to take out the towers mortars and cannons protecting the mines, etc....at the same time you release wiz or archers, etc, to kill the mines, you can get shot up pretty bad if the balloons don't get them all/enough of them....so, it typically pays to do the take outs first, then, if its SAFE, send in the mop up crew.
Don't send the drag until the AD is blown, or you toast the drag in a matter of seconds.
Don't send a pack of hogs until 1 hog has blown the bombs, etc. Kill the troops or royals in the way before sending in your guys who get beat up from behind as they lumber along.
And so forth.