As my opinon,  think there are two types of card decks, the high elxir cost card deck (or hec-CD), whch average is 4.5 elixir or more, and the low elxir cost card deck (or lec-CD), which elixir average is 4.4 or less.

In a norml card deck you have the tank units, Giants, Ballons, Knight, Golem or even a P.E.K.K.A., you have the dtraction unit, for dstractng attacks from your opponent like skeletons, goblins, minions, the long range unit, that can defend or attack behkd a tanking troop such as spear goblins, a musketeer, a bomber, archers; ths troops also make the role of the troop you need to defend from an ar attack, you can also take a support troop as the prince, he mini-P.E.K.K.A., the witch or troops like that; another option is to bring a buildng card, to defend or distract enemy attacks, and finally, the spell, the spell is necesary for that moment there ar a few seconds and you are losing by one and you have that one tower wth 150 or less hitponts less, your hands get sweaty and you dont know what to do to en with that bunch of enemy troops dong everything they can to defend ther last crown, well you cand just play the wizard role aaaaaaand... fireball, you saved your trophies, or you can trow a lighting, a zap, arrows, a gobln barrel etc..

Tell me in the comments what strategies do you use, I didnt said in an explicit way what I use because Im constatly changing between my tankng troop, my support troop, etc. also between a hec-CD and a lec-CD, it sounds terrible by the way.