I've written about wardrobe and wardrobe choices a bit before.
But because of some recent industrial work, I'm thinking about it again.
I'm thinking about how it's helpful for an actor to know what colors they look good in, and to know what colors and clothing styles work well on camera. Lots of us know this already but thanks City of Alberquerque for spelling it out so clearly! To their page I'd add the following: avoid logos/writing/images on your clothing, but everything else they're saying is spot on.
For industrials in particular, it's helpful to know the difference between formal business attire and business casual. This page has some great descriptions and images, maybe a little bit more for women than men. Here in the Bay Area, with Silicon Valley's influence, we're sometimes asked for a slightly more hip version of business casual, so you may need to ask for clarification if things aren't clear. Another great way to figure out where your current project or audition falls on the formal to casual spectrum is to go to the website for the client company or to companies w/a similar culture/industry, and see what the people are wearing in photos on their site.
I'm not the most conservative dresser in my everyday life, but I keep a few pieces on hand for things that I'm often asked to do. I have my mom slacks (light colored khakis) and a few sweaters, as well as a few business suits, with the appropriate accessories. I've watched for when the suits go on clearance at department stores, and taken a few runs through places like Nordstrom Rack, H&M, etc. to round out what I need. Clothing swaps with friends have also helped me round out these areas of my wardrobe.
I make sure that I keep all of this stuff clean and ready to go too. It sucks to have to spend extra money on a rush turnaround at the dry cleaners.
And last of all, I've got a garment bag for hauling too and from set! It's always surprising to me when people show up w/stuff jammed in grocery bags, or just carrying a bunch of shirts on hangers in from their car. Both you and the clothes look better and more pro when you can bring it all in in a good bag.