Not being nervous is pretty much the factor. I'm one of the worst snub PVP-ers inside the community, but I remember that not so long time ago I dropped into one group combat not even caring about proper strafing and I had approached that somewhat accepting my ship being "dieded" in the first 20 seconds. I ended up with scoring two kills. And survived.
That was the most What The Heck moment I ever had on Discovery.
Keep pvp-ing with good pvp'ers and force yourself to know you'll get reduced. Somehow you will end up learning how to defend yourself against aces.
A good tip when you're outside of conn is flying such ship in which you know you'll die, like a Barghest. In this way you will tend to fly more relaxed and such and you will improve your day by day flight outside conn . F/e I started to fly bombers outside conn without a hope of surviving, and after dying quite a lot of times I managed to understand how to do it.
~PVP means patience and perseverance . Don't get too mad at it, it comes with time
For me the procedure is always the same, in every game.
Example: I was bad in CSS, mostly played for fun until I wanted to become better. So I started to play on AIM maps, where you had all the time 1v1's to train your skill. I did that roughly around a week, every day 4-5 hours. After that time I became decent or as other People say above average and won most of my 1v1's.
In Freelancer it was the same, I was really bad, completly new to this genre and wasn't even aware of weapongroups, engine kill and all the other stuff.
I wanted to become a good pvper, so I started to pew in conn mostly 6-7 hours each day, after around 2 weeks my aim became quite good and I met some people who were able to beat me in conn, it was a really nice when you kill the people that managed to kill you without even loosing their shield.
Take your time, Focus on that what you want, if you want to become good in PvP in this game, you need to spent time, ask yourself why you lost that fight, where was your mistake, where did you lost the upperhand in this fight. If you can answer all this questions in every fight, you will stop to make this mistakes and become better.
Of course, maybe you will need a month, or even two months to become above average, but if you manage that, you can see that your skill curve will increase more and more.
"I always want to be one of the best, if I can't be the best. / Ich möchte immer einer der besten sein, wenn ich nicht der beste bin" That's my Motto, and so far it always worked.
Ps. I saw quite alot of people fighting me and becoming better and better, when they even finally managed to win fights against me, even if it was close, they still managed to beat me.