Like the other reply, being fit is most important, clothes will hang better.

Buy used/vintage designer clothes. Stick to neutrals: blues, khakis, grays, black and white and the one or two colors that looks good on you (red or whatever). Accessories are where you express yourself, so keep the funky trendy patterns to ties, socks, handkerchiefs (if wearing a suit) or even hats.

Find a good tailor and have him take in/let out your clothes to provide an even more structured fit for your body shape (for example, some men have longer legs or wider shoulders/hips). Most celebrities have even their basic t-shirts tailored.

Staying fit, keeping the neutral colors and buying well-made clothes will extend the life of your wardrobe immensely as well as your save money. Also, learn how to properly care for your clothing.

My man does this, and he's had the same clothes for going on 20 years now. He has a penchant for funky t-shirts and will throw a nice button-up over it if he's going casual. His biggest wardrobe investment is his work clothes (construction), he will have to buy new shorts every 2-3 years because those will get holes, covered in paint or the drawstring wears out.

Great. You have it much easier.

Job one is to realize you probably don't want to be a fashionable man, but a well-dressed man.

Your highest priority is fit. Fit is almost everything.

Apart from that, buy expensive shit used or on sale. Pique polos and nice blue jeans that actually fit (bring an honest straight woman to the store, ideally one you're fucking) are hard to fuck up. Get some khakis and button downs.

Shoes are a whole other universe, but basically trainers are just for the gym. Grab some Clark's desert boots or something that looks like them but with more structure if you're not sure for daily drivers.

You need shiny black shoes. Probably cap toe. $300 and up. Don't pay that much.

There's regional variation, but men's clothes are fairly straightforward.