I hate the words fashion and style.
The most with-it-sartorially guys I've seen are Indian villagers - next time you're on a train in Gujarat or Tamil Nadu, take a look outside and you'll know what I mean. I saw a couple of Gond tribal boys in a small railway station somewhere in AP, still remember them after decades: whiplash-thin, hair tied in a bun with wooden beads, tattoos on their faces, spotless white loincloth, quietly sitting on haunches, smoking cheroots in the shade of a tree, looking at the train. This is what defines the bleeding edge of style, in my life so far.
Here's what I think about the clothes we wear. This is not a guide, just what I think, though I suspect there's a preachy note.
If you need a guide, ask Ritu Beri or someone...:

Jeans look like uniform these days. Also, they make girls look like BPO staffers. But if you insist, only 501s or Uniqlo. Avoid the Levi's Damien Hirst stuff, too NRI.
99% of tees look crap, esp the ones with big logos. And stupid lines, and wannabe graphics ripped off from 80s underground magazines. Design your own t-shirts if you're 20-25, fashion brands don't understand you. I like (some) Playclan tees, but wear them not more than twice a month, or they'll lose their aura. Avoid Ed Hardy, too mall culture - I have an Ed Hardly, I wear it to nightclubs to make fun of those wearing originals.
Uniqlo are the only guys who've got it. Clothes you can wear anywhere... you can sleep in them and go to office next day.
Wear linen, lots of it, if you're 30 plus. Get yr linens stitched from Mohd. Usman Khadi Bhandar off Northern Avenue (it's a garage), that's where stylish MPs from Orissa go. Or D. Vaish, in CP. Givo linen trousers are nice, good value too, they're made/stitched in Manesar so cheap in Delhi.
Avoid Armani, too new money. Avoid all big luxury labels, too NRI. Wait for 5 years, they've just come in so the rush of new money to places like Emporio, etc.
Wear vivid colours occasionally, but don't let Allen Solly define what's vivid, they're too 90s. If you must, avoid the maroon button-down-collar shirt, only Prannoy Roy wears it. Girls, don't wear anything Barkha Dutt wears, too wannabe. Don't copy her haircut either, looks like it's from the Benaras ghats. Though if you're from Benaras, you know what taste is, you shouldn't be reading this.
Never wear pointed cowboy shoes, if you insist, don't come near me. Avoid Crocs - ugh. And Woodland-type sandals with 3/4 cargo pants, too advertising.
Formal shoes, handmade Oxfords from khan Market, nothing else. Wear leather slippers whenever possible, ideally handmade in Italy. Expensive - about 4k - but worth it. Try Balujas too, good range.
Don't wear heavy watches, they suggest you got married in Gurgaon recently. Wear a simple Timex - I prefer HMT though I don't have one. And why do you need a watch, your mobile has a clock.
Half-sleeved shirts, always a bush shirt (straight, triangular cut at bottom). Fab India is nice but good luck with the fading colours. Anokhi is very good, you'll find them at smaller malls (Futurebrand I think).
Full-sleeved, avoid Allen Solly like I said, you'll look like an Eureka Forbes regional manager. Louis Phillippe shirts are good, but I try and buy dress shirts from Nehru Place pavement shops, they're used Salvation Army stuff, but original Armani etc. at Rs 100 approximately.
Many of my biker friends in the US never buy new clothes, they buy from 'thrift stores', and they're way cooler than most 'mainstream' Americans their age. They're 'subculture' graphic artists, hackers, musicians, etc., and strangely, icons for advertising agencies selling middle-of-the-road fashion brands like Tommy Hilfiger, etc. :)
Suit, always charcoal black, lightweight. You should be able to board a DTC bus in it - must be extremely durable. The best tailors in Asia are in Shanghai gullies, very cheap.
White shirt, yellow tie. Don't overdo it though, you'll look like a German car salesman in Pragati Maidan.
Girls, wear cotton dresses with lots of flowers. Benetton is good. All women look beautiful in a garden, as Vivienne Westwood once said. I like Promod too, beautiful cuts, inexpensive. Nautical 50s look.
Avoid salwar kurtas, they look like nightwear. Unless it's expensive khadi.
Avoid Sabyasachi, all Marwari women from Calcutta wear Sabyasachi to look cool.
Men's underwear, Rupa. They're actually more comfortable in the Indian climate, than Jockey etc.
Socks, don't wear Reebok socks with formal shoes. Don't ask why.
Don't wear American university tshirts, unless you're from that university. It's like pasting a Turbo sticker on a Maruti 800.
Don't wear baseball caps, unless you're at a baseball game. I don't think we play baseball in India, especially indoors.
Don't wear aviator glasses, unless you're David Hasslehoff. Men shouldn't wear dark glasses, makes them look like wimps.
Ladies, those huge round glasses perched high on your forehead are dangerous. They could make you look silly or sexy. I find 95% silly. Your call.
Don't tie those red puja strings around your wrist, that's for temples, not offices. (I'm a hardcore Hindu, but keep religion a private affair.)
If you can carry off a dhoti/saree, go for it. Nothing can touch Indian traditional, it's way out there aesthetically. Nothing, absolutely nothing, comes close. That's what Nirad Chowdhuri and Naipaul said too.
Finally, understand and accept your father or mother has better taste than you. They grew up in the 50s/60s and got the best of Indian and Western. Things started going downhill after that.
If your parents grew up in the 70s/80s, you don't need to read this, your parents do.