Newbie guide (includes tips on making money):
http://wiki.project1999.com/Players:Newbie
In terms of joining a guild, just keep at it. Messaging guilds you see around and asking to talk to officers is a good way to go about it.
I wouldn't worry too much about gear but I would prioritize getting a good primary weapon. Farm up 100-200 platinum, go to EC, and buy something cheap. Damage/delay ratio is important, as is having a high damage (better backstabs). Stuff you can buy in EC will be way better than anything you can quest/loot yourself.
In terms of grouping, as a rogue you will be in high demand, regardless of your gear.