The two head items thing is simple, one is effectively equipped and one is equipped in the appearance slot and is only for the visuals and has no effect whatsoever.
As for being ganked, well, that's what I hear in all mmorpg's pvp. It's an easy kill for those that do it, it isn't fun though.
PvE servers do have pvp, but it is not much and I doubt you would like it.
As for tips, don't walk around alone or as little as possible. Try a good guild and do guild groups.
Being in a good guild would also give you better access to better equipment, mastercrafted armour is usually better than treasured, but legendary and fabled is better still. (still wear a lvl 70 fabled chest item for instance at lvl 80 myself) If you have to buy it all from the broker, then it gets expensive. Guilds tend to run instances which will drop the good stuff too.
Try to update your armour, make sure your spells are at least adept I (master is naturally much better but also a lot more expensive, I never bothered with those before hitting max level).