Sending in a lone troop to attack the enemy can lead to failures in most cases so try to send at least another one to assist them. One good strategy is to drop a troop at the back the arena and wait for them to make their way into enemy territory while your elixir charges up and you can also see how the enemy reacts to your troop deployment, and once they cross the bridge, you can send in support to assist them.
Watch people on Youtube and take note of their decks and strategize. Copying their decks is a good start to understanding how they play but make sure to make changes to it because many other players will also be using their deck if they’re famous. Other than that, make sure to watch your own old matches to see where you made mistakes, where you predicted wrong and to see how you can improve. https://modsbeast.blogspot.com/p/home.html
Pay attention to the cards your opponent uses and watch for patterns. This can lead to both, great offensive moves and defensive counters both which the opponent might not expect. Pay attention to the meta of the game which will help you understand your opponent’s moves and deck. If you time your troop deployment correctly based on correct predictions, the opponent will be caught off-guard, giving you the advantage.
Once the match starts, assess your cards and determine whether or not you want to go on the offensive. Always going on the offensive is not a smart move so quickly assess the situation and if you think waiting for your opening and countering is a better move then do that. While there is luck involved in the game, there is also a lot of strategy and quick thinking required that can help you turn the tide in your favour.