There is a -LOT- that goes into a successful PC and if I sat here and tried to explain it all it would take me several very, very, very long posts.

But what I will say is that PC in and of it's entirety comes down to how well your team works together and primarily why 'A-teams' are still a thing, even though we'd like to believe that phenomenon died out back in Uprising.

Thing is, you can't prepare for a PC as a single person. Every module, every piece of equipment, every weapon and every dropsuit is part of one big teamwork cog that all forms a victory. You run a Caldari Sentinel? Proooobably not going to be much benefit to the team in a city-fight as Logis have a harder time keeping you alive and you're extremely vulnerable to Flux strikes, as opposed to an Amarr Sentinel which would likely shrug it off and be repped by a logi-pal.

So to prepare for PC, you really need to look at what the rest of your team is doing.

How are we getting to the objectives when the match starts?
Who are fighting against? What are their known tactics?
Do we need to worry about roof-top play?
Where do we place uplinks? Where do we spawn?
What fits do we spawn in with and why will it work?
What do we do if our plan falls apart? Where do we transition/can we transition easily?

The baseline preparation is to have -ONE- role that you are proto'd out with, be it Assault, Sentinel, whatever. But the finesse of that role stems from what you're trying to accomplish in order to get that victory.

I have a fit called the 'Guerilla' fit and it is the -ONLY- Gallente Assault fit I have in my line-up. It's express purpose is to have moderately high armor with high repair rate, myrofibrils, and a cardiac regulator. It has Viziam Flux Dropuplinks (which is probably the only consistent thing you'll ever have in all of your fittings) and it's entire purpose is for me to have the mobility to get into tough locations (jumping over walls in the outpost) to place uplinks and defend them long enough for my team to take over. It serves literally no other purpose. It is a close range brawler with just enough survivability for my team to spawn in on my tactically placed uplinks that I could only get behind enemy lines with the mobility the suit offers.

Think about what role you want to play for your team, how it benefits them, how you can hallmark it, and how it will win you match after match. That is the best way to prepare for PC.