Je tombe amoureux de toi = I am falling in love with you (c'est ce qui se passe en ce moment) Je tombe amoureux de toi = I fall in love with you (ce qui se passe régulièrement, p ex Every time I hear your voice I fall in love with you ; = a very unusual sentence) Je regarde la télé, que fais tu? = I am watching the tv (right now) what are you doing? Je regarde la télé avant de me coucher = I watch tv before going to bed (what I usually / regularly do)

Je tombe amoureux de toi means the action is on, not finished so I would translate by I am falling in love with you. But I am french and I always fall in love... :)