Level 10 opens up dungeons which will boost your levels up nicely, compared to regular quests it’ll be like someone hookes your character up with a bottle of nitrous. Think I went up 3 levels in my first dungeon 😂 Other important levels early on that I can think of is that at lvl 15 you get a free mount, makes moving across the map a bit easier but you should also visit stablemasters once a day to upgrade your riding skills. Not sure when the pvp area opens up as I’ve stayed away from that for now 😅
The other great thing about dungeons is you will be getting better loot, it wont be the kind of loot you hold on to for very long but it’ll definetly be a big upgrade from the usual stuff you can find.
The best people to be asking are probably @Nutcuttlit and @J&B though as they know the game very well having played it for years.