At level 55 you get access to the end game gear. You need recipe books and deathtoll(pvp currency) or dome points(dome instance points) to craft end game weapons. For end game armor, you need to get a recipe book from The Outpost and materials around epsilon and other zones. You can either try to learn dome with someone from the community or play pvp, either Bloodsports(queued pvp) or open world pvp by flagging.(/pvp) The community is really small but you can still find players that do dome. As for pvp, try queuing for bloodsports or ask in chat if anyone is doing pvp. Just remember most pvp players have been playing for years so the pvp learning curve is quite steep if you havent been doing it while leveling up.
P.S. to get to 55 grind white crow camp near citadel or find someone to do dome with and just farm the bugs on the first stage