I was terrible too. I still am most likely.
But, when I played CF I did have a well known niche that I played, and I usually had moderate success with it.

That to me is the best advice I can give. The people who are terrible at CF are people who play something different every time, and reroll every 100 or so hours. You don't learn the ins and outs of a build in that amount of time, and unless you are really attentive to how other players play builds, you can only get so much through observation of others. And fighting a giant sword spec depends on what build you are playing, so you may have a base, but there is always a learning curve to a new class/build.

The reason I became average in PK was because I played the same class repeatedly, and learned how to do it well. The true vets can learn and adapt builds fairly easily at this point because they have a deep well of knowledge. That always felt more like work than fun for me, which is why I have always sucked at any build that was not a bard. Even if I know in theory how to make other builds work, I never had the patience for the execution of them.

So my advice is find something you really enjoy playing. Play it. Con die. Do it again. Con die. Do it again. Age die.

By char 2 things should get easier and you'll start holding your own, because everything won't be as new, and you'll adapt more quickly as your comfort level with the build's strengths and weaknesses grows. By the third time, you should be so fluid with the build that you won't make as many mistakes, you'll know how to gear and prep, and most importantly, how to fight others. You'll realize most opponents follow that same tactics for the same builds, so after seeing them a few time, they should be easier to fight.

For me, it was bards. Find one that works for you that you enjoy and start there. Just pick something that has moderate PK potential.