The best way of getting gud, is trough Trial and Error.

If one thing doesn't work out for you, maybe you need to change your overall approach on the Situation as a whole. Keep in mind that most FFXIV Players are rather fond of a "rush metagame" for which we can blame Frontline Roulette, Feast and even Savage Raiding to a degree.

Depending on what you play, you can use this to your advantage. Get creative and dont fear losing, if one thing doesnt work out, another will. The current Job design in PvP is alot more flexible than one might think.

I also recomment recording some matches you play (or watch Streamers play), that way you can also gain great insight on how People play during a match.