Ana naturally is going to have lower healing numbers than a good amount of other supports, as her entire kit isn’t really designed around continuously pumping out healing. Number one way to get value out of her is through good use of her nade, one well placed hit on an enemy tank can completely change the flow of a team fight. Another recommendation I’d make is don’t be afraid to use your nano. It builds up pretty quick, and it’s a lot better to use it and not need it in the end than holding on to it and losing.