Here are pictures of the left hand. Notice the curved fingers and elbow that is up but in a natural position and not too high.
To strengthen the left hand promote this technique, do the ‘crawling exercise’. Place all four fingers down on the G string as if to play the note B in first position. Move one finger at a time over to the D string. So, the first finger moves to the D while the rest stay on G. Then move the second finger, then 3/4. At any given time, all finger should be depressed (except while moving a finger).