Chick techs rule!
Back then I used to wear what I called a "girlie tux" - nice black jacket and pants and under was a top/vest with rhinestone buttons. Not sure what the dress code is or how well they'd strictly enforce it these days. I'm always on the look out for nice but cheap 'formal' looking outfits. I found a long (to the knees) crushed velvet jacket for $15 that I wear with slinky black pants. The trick is finding comfortable shoes that you can run around the ship with . . and you will have a lot of running around . . esp on a formal night.
Also remember to bring a notebook and write EVERYTHING down - don't know how long your handover will be with the previous tech, but make you take note of when and where . . and equipment patches, band setups, etc as you'll get an amazing heap of info thrown at you and will be responsible for doing it on your own the next time around by yourself.
As lounge tech, you do get the run of the ship, but . . just think if YOU go to a nice resort. You don't see the room cleaners, cooks, wait staff etc hanging out enjoying themselves. You're there to work, and there's a whole 'nother social scene in the crew areas. You can watch the main room shows from the sound/light booth that's in the balcony - and most likely there still are restrictions about staff actually using lounges and restaurants. You'll find that out when you board . . .