In my study, I got a Cronbach alpha score of .61 for 6 item scale (3subscale). How do I increase the score or is there any way to justify this alpha score?
Generally speaking, higher the number of items, better the scores. You may also check to see dimensionality of the items. Explanatory factors analysis can help you do that. If the items do not load in a single scale, see if deletion of some items can help the score.