New Player
Welcome return.
Perhaps, you might find tips in the PvP sub-forum.
Barring that, I would suggest continuing to level up your characters in Core Tyria, then either acquire Living World Season Two, or, at least, spend a good amount of time in the Maguuma Wastes.
Good luck.
Unfortunately, not having HoT (and the associated elite specialization for the class you choose) is a major problem in PvP. A quick glance at metabattle indicates that only ranger and mesmer have somewhat competitive builds that don’t feature the elite specialization (and they still aren’t rated top tier). Metabattle isn’t the ultimate authority on builds, but I think it’s safe to say you’re going to feel the lack of HoT when competing in PvP.
As above without HoT you will not have the same “impact” as others in sPvP. Which is a shame because if you were to play sPvP you would be able to get free exotic berserker gear whilst gaining tomes of knowledge so you wouldn’t need to level up your character in the open world. On season you will also be able to get free ascended gear, including one weapon or armour piece, a backpiece and as many trinkets as you can farm.
You could also play WvW to level up just running around with the zerg but you might find that a bit boring. I’ve only levelled one char in the open world and I wish I didn’t because I could’ve gotten to play each class in sPvP and built up tomes and exotic gear in the meantime. Since then I have levelled every class with tomes and geared each for free. The great thing about gw2 is that once you have one level 80 you build tomes so fast you don’t need to play in the open world.
Personally I would recommend picking up HoT and having some fun in sPvP, learning the ins and outs of all the different classes, which is what I would do if I could go back to day one x)