Hi, welcome to the game! The best advice I can offer you is to read up on some of the guides. The new player guide is probably good. The game doesn't have any sort of tutorial to speak of and therefor has a large learning curve, but the community is very helpful and informative.
The game has improved a lot since the initial release. I used to have terrible, almost unplayable lag (especially with the UI) and it seems like a lot of that has cleared up. The main reason I quit was because I wanted to do several tradeskills and the inventory was just too limited. It had I think like 75 spaces, you couldn't sort it and items only stacked up to 12. Now they stack to 99, you have 100 spaces and you can hire two retainers (NPCs that hold your stuff and can sell some things for you) for an addition 100 spaces each. So they fixed my major complaints. The next update is supposed to include some new content too so we're excited.