As you continue to play through Clash Royale, you'll quickly learn that it's a poor strategy to send one troop type in all alone on a rush. Your best bet is to wait for your elixir to charge up so that you're able to drop at least two troops at one time to maximize your effectiveness. For example, say you want to send in a Giant. If you pair him with a flying troop (Minions or a Baby Dragon), your opponent's troops will lock on and attack the Giant, allowing your air troops to offer support and pick off the ground troops. Cash Royale Hack
Another great strategy for playing cards is to drop your troop at the back of the arena, and wait for them to work their way through your half of the arena. This is effective for a couple of reasons: firstly, it allows you to recharge your Elixir while your troop remains (mostly) safe from your opponent's attacks, it'll let you see how they react to the troop you drop, and as your first troop begins to cross the bridge, you'll want to drop your second troop (or more) to to join them on the rush.