Some people like to use their elixir wisely but others tend to spend all their elixir once they get the chance in the beginning.
They cab always back fire someone can use a skeleton army then mirror then clone but others use mega knight to block them off their tower and the advantage it the spawn- area damage. People can use arrows and only use 3 elixir and the other player using all 10 of their elixir on skeleton mirror then clone.
A good way to start is to wait for the other player to spawn a troop, then look at what you have in your current hand. Try to look for something to counter that troop. EX. Use baby dragon for barbarians. People that use cards like the prince or barbarians in the beginning of the game, usually people who do will get their elixir wasted because the defending player is able to use a spell or use a skeleton army then clone and still have enough elixir to use another clone or skeleton army (x2) then clone (x1).
Depending on what deck they have it gives you bad and good odds. Even when having the lower hand you can still use certain decks , like for example if the opponent uses a lavaloon deck and you have an X-Bow deck you can counter with an ice spirit then use minions if equipped then when the lava hound starts to get to very low health, use poison or freeze spell.