The only time you should ignore healing and DPS is when you hit an enrage skill and you don't need to keep DPS alive. :-) Even though if you miss a few times, those few DoTs and whatever you throw at the boss can get a clear or not. Damage is damage ^-^

If you do start incorporating DPS into your playstyle, if you can pick out recovery phases of an encounter (low damage that can be sustained by heal over times or simple Cures), start with throwing only DoTs up. Once you become more comfortable with both healing & MP management, you can throw in extra DPS in the long run.