your left hand is no different that the right hand, its pretty obvious your right handed, so you dribble with that, most people do, but you want to obviously keep the left hand pretty strong, i had this problem alot when i first started playing, (im left handed) couldnt even lay up with my right because i practiced only one way, like youngtricker said, 2 balls, or just dribble with your left, put your other hand inside your top so you cant use it and just dribble, its all practice

everything in basketball is all practice, just keep going and keep training it and before you know it, youll be just as good, theres no real "left hand" dribbles, just do the same youd do with your right hand, with your left and your set