Group Dungeons help with this, IMO. You'll get much better at looking for tells to identify skills and you'll become more adept at movement, synergy, and being out of the way.

Beyond that, it does take time to find the skill combination for your particular class, especially in PvP.

Skill plays a factor, luck plays a factor, experience plays a huge factor.

Keep at it and you will improve. Run with groups where you can and you can practice your skills and combinations in a bit more forgiving environment. The delves in Cyro do help, too. You will be fighting higher level enemies in addition to having to remain aware of the PC enemies that can arrive at any given moment.

Bear in mind, even later, it's not unusual to 'lock up' during a fast paced fight, and even when you get used to to it, you will still die from time to time.

Practice it on harder and harder PvE content and you will find that it will carry over to improved PvP skill.

If you've done well in other games, you'll do well in this one. Just takes time.

(Last thing: Take it in small doses. If you find you're losing focus or starting to get frustrated, try something else for a bit. You can always come back later. If you stay to the point where you feel there is no hope, there won't be.)

You'll get there!