"To wait for someone" can be translated into Spanish as "esperar a alguien". So "waiting for you" should be translated as "esperándote (a ti)". As you can see, "a ti" is not necessary because you make the word "esperando" end in "te". In case the sentence was "I was waiting for my girlfriend", the translation would be "estaba esperando a mi novia". I hope it was helpful! Keep it up!