If your computer is fast enough, I suggest recording your own game play with recording software like OBS (Open Broadcasting Software). Personally, I record my own game play every time I raid for Savage or Ultimate. It is a habit I developed when I played in other organized group-based games.

As a DPS, it is imperative to always be casting and keep your GCD rolling. Higher skilled players use their strongest moves when party raid buffs are available in order to maximize damage. Reviewing a strategy guide is helpful, but you may have to tailor your play to each specific situation you encounter.

After reviewing video, I notice a lot of things that could have been executed better. When you are playing in the moment, you may not notice the sub-optimal play. For example, not pressing enough buttons or pressing buttons in the wrong order.