This is mostly horrible advice.
1. Women (especially 20-something girlfriends) have no idea how men dress properly
2. Stay away from solid colored shirts, unless they are white, blue, or maybe salmon. And I don't mean teal blue. Stay the hell away from black. Green? Are you serious?
3. Do not match tie and shirt color. There should be some visual interest. A good rule of thumb is to pick a tie darker than your shirt, and if they're both patterned, use patterns of different sizes.
Don't dress like you're going to an Indian wedding -- neon colors, ridiculously complicated prints, black on black, dark red on dark red -- this all looks horrible.
Honestly, 3 white shirts and 3 light blue shirts plus a collection of solid colored and simply-patterned ties is what you want.
Here,
read this gigantic thread on conservative business attire. In all likelihood, those guys are wearing ties and shirts worth more than your cumulative debt, so ignore the brands. Just focus on the well-executed combinations of patterns and colors.