1. Leave money in your clothing budget for alteration. A nice pair of pants with a bunch of fabric balled up around your ankles does not look like a nice pair of pants. Get something less expensive and alter it.
2. Grey pants match damn near anything. If you ask the cleaners, they'll press out the crease that runs down the legs and look a lot less "fussy."
3. Gross generalization, but $150 shoes last more than twice as long as $75 shoes. Hit up somewhere like Nordstrom Rack for good shoes. Same principal applies to belts.
4. If you buy a suit, avoid the current style of really skinny lapels and too-short sleeves and pants because it's going to look dated fast. Get a grey or blue two button suit, which is pretty versatile. Avoid big or padded shoulders, giant arm holes. Consider vents on each side ("double vented") rather than one vent in back which apparntly was designed for sitting in a saddle. And for god's sake don't buy a jacket you can't button comfortably. Then get it altered.
5. Don't feel compelled to use those little plastic collar points.
6. Plain shirt? Patterned tie. Or vice versa. Of you need to mix patterns, mix a large one with a different small one, but avoid this unless/until you know what you are doing. If you wear a tie, strongly consider a jacket.