Ah, the joys of levelling a thief - even matches that wipe the floor with you, party members that think you're just a bad melee... read up in the Job Forums under Thief if you want to really get depressed.
However, it pays off. I lvl'd thief to 30 as my first class, and while the road up is wrought with hazards, the view from the top is amazing. Thieves make the money that
every class needs later on. After seeing me run around farming, many people in my LS are starting to lvl thieves to at least 15 just so they can farm.
I'm levelling RNG, and if you're new you may not realize how expensive that is. Well, not only can I afford the best weapons, always have arrows, and still have enough for toys, I am also working on
all my craft skills (three are above 10 so far), helping people find those ever-so-rare quest items, and in general having a blast.
Thieves are the go-to guys and gals for *any* treasure hunt - be it Kazam keys, special equipment, quest items, etc.
Then, there's the higher-lvl partying. Stack your Sneak Attack on a Fast Blade and watch other party members drool at the DMG. Add Trick Attack to it, and there's no question that you provide a useful function to the group outside gilfinder and treasure hunter.
Try to stick with LS members or friends when you can, or actively ask to be in groups when you can't. Tell WARs and other melee what needs to happen for you to Sneak. Explain Treasure Hunter and Gil Finder to them. Discretion may be the better part of valor, but education is a close second.
If all else fails, pull a SA/FB. That should make them sit up and take notice.
Steal with impunity, sneak with inventiveness, and grow with integrity. And at the end of it all, just remember: property *is* theft, so we're all thieves at heart