Make sure the derailleur cage height and sight line are positioned correctly before proceeding with further adjustments. It sounds like you are having cable tension problems, so make sure this is checked next. You may need to adjust the cable to compensate for stretching that has occurred from normal service. You will need to set your limit screws next, and make these adjustments by pulling on the cables, and not using the shift levers. Be sure to set your limit screws on the front while also having your chain on the inner and outermost extremes on the rear to eliminate rubbing on the derailleur cage on the innermost and outer front chain rings. Once this is set, you can address any indexing issues. Park has a good tutorial on their website with lots of further information. Good luck!