New Blade And Soul player incoming
Going to assume you will be F2P player for now at least.
Sigh where to begin, there are a crapton of tips I can give to make your new in-game life a smoother ride.
All classes are fit for both PVE and PVP, some may have better tools in certain situations, some may have more aoe abilities, some may have more multi or single target dps cycles and some may be more flashy than others. But when it comes down to it, you should find a class that's best for you on your own. I'd suggest looking at class videos as making/deleting character is a pain right now if you don't like a certain class.
Focus on leveling for now, do all the quests you come across and any dailies in the area for fast leveling. You will find that you'll be very short on inventory space in the beginning and it won't get much better without spending some $$$ for Dragon Pouches in the cash shop. Only advice I can give you is don't dwell on the loose soul shields you get, sell/disenchant them as soon as you get them to save space. Also use the abundance of weapons you get while leveling to enchant your hongmoon weapon once you get it. When in town find the vaultkeeper and use the secondary tab to keep stackable items in there and everything else in the primary tab.
The first wheel of fortune you come across will have some goodies in there, namely your temporary solid soul shield and weapon breakthrough fodder from the weapon chest. I can't remember if the weapons are tradable or not but if they aren't you will have to spend some keys to try and RNG your way through it. And after you get it hold on to it until you can use it for breakthrough for your hongmoon weapon. Don't bother enchanting soul shield until you get the final ones in end-game, it's a waste of Blade & Soul Gold and time. Although some lesser soul shields will cost nothing to enchant then by all means go for it.
Surveys, they will give you these gems that you can use to enchant your equipment. Do NOT use them right away as it is wasted potential. Once you upgraded your weapon the first time or second time check and see if using the gem gives near 100% exp so you know you're getting the most out of it. And always always pay attention to the cost of enchanting as certain weapons/accessories you use to enchant with will cost more than others later on.
Your first heroic dungeon: Blackram Narrows will be around lv 20 ish, here you will find the next breakthrough fodder for your weapon and your accessories. Do NOT bid over 15 copper for these as you have a good chance to get them from the daily box from beating the dungeon. Even though they make good enchant fodder early on. Same goes for blight fangs you won't need more than you'll get from the quests until later on when you have more Blade And Soul Gold to bid with.
The game is good even for F2P peeps. The only real benefits of getting a subscription is if you don't want to wait in queue for a long time; varies by time of day and what day. There are no items in the NCoin store that gives you stat boosts that puts you in an advantage against another player, especially in PvP. It's almost all cosmetic and how you want your character to look.
It's ok to go with a newer server. It will give you better queue times and whenever you want to PvP or do dungeons, there are cross-server matching options which let you play with people from other servers.
Follow these steps and you should have a very easy time early game, after that you'll know what to do.