Erion is a fun game with a lot to explore, but it does have its issues, two in particular, slow progress and lack of missions.

Pvp and challenge isn't something I care for too much, so it never bothered me that I was able to win the house contest in my first month, likewise I actually like the fact that in Erion its possible to win global quests when the game generates them, in aardwolf for example you don't have a cats chance in hell at global quests since there are always so many other people doing them, many of whom are seasoned players who know the game inside out. Likewise I like the fact that  Erion it is actually possible to buy quest eq and for it to be useful, in Aardwolf you need literally thousands of quest points all the time.

I also enjoy the random systems in erion  such as chocolate bunnies, sigil drops, crystal shards, the collossium etc, other players (especially the devs and immortals), in Erion are also nice people (very different from Aardwolf), Erion also has rather more fun abilities to use, you don't just type "kill" and wait, but get interesting techniques to play with (I love being an archer and shooting at a distance).

The really problem with Erion really  that levelling in the game is very slow, and since many of the npc missions are intended to go with faster levelling, this means your rather stuck at lower levels exploring the same areas. This is why I don't play Erion as much as I used to, which is a shame.

I did hear  originally had more xp from monsters and so faster levelling and that that got dropped a few years ago, its a shame that either the devs can't add more missions or drop the xp rate so that you can explore more of the game.

Generally speaking, if you want quests and story Erion and Aardwolf aren't the games to play, they are hack n slashers.

Aardwolf progress is faster, but combat is less interesting being mostly a case of typing "spellup" and then fire and forget, also while you progress faster and see more zones  in aardwolf many are random and don't feel like they fit with the game wor.d
Another huuuuuuge! problem with Aardwolf is that  npc goals in the game (like missions or quests in other games), are close to impossible due to guess the verb and random clues, and other players are generally not too helpful with them.

Erion is the smaller game, has more random stuff to keep you going and possible progress with the autoquests as well as far nicer devs, but levelling for xp is much harder and while the npc missions are far more possible and other players are far nicer about helping you with them there aren't as many, ---- though being as the aardwolf missions  so impossible it's barely even worth your time attempting them both games are probably much of a muchness for npc quests, its just a question of whether you prefer a game with lots of quests that are close to impossible due to obscurity and players who don't help, or a game with fewer quests which are! actually possible and fewer players, but ones who do .

Now as to your immediate questions.

Erion has a really useful eq search command. You can use this to find npc equipment which is close to your level and gives bonuses.
Try help eq search. As a thief you probably want similar equipment to what I use as an archer, namely equipment with agility bonuses and armor class.

Also remember quest equipment helps, and check the university since there is some useful gear there, including gear for pin slots which you won't find elsewhere.

As to skills.

Remember that in Erion abilities make a difference. As a thief try using throw kick and backstab, also remember to check the theive's guild for some of the thief specific  that you can buy with those quest points.

If your not sure what to do with gold, you can convert into mudpies, or buy collossium tickets, since again the collossium has some good gear.

Hth.

I might get back on Erion myself. My char is called tanquest.