Ok, you young idiot.
Firstly - the good news. You'll still have hair when you turn 30. But not by much. Also, you're married to an awesome woman. I don't want to spill the beans about that here (why take away from the joy of discovery?). All I will say is - keep an active interest in audio products, especially ones that play lossless files. Also, yes - you'll end up in MICA and advertising, like you wanted. Living the dream of wearing shorts to office and making PPTs at 11 PM.
However, life is not all hunky-dory. There are going to be some ups and some very downing downs, but I can't tell you about them, because, heck, you love Back To The Future as much as I do, and you know what happens when you go mucking around with the space-time continuum too much.
However, here's some advice for you. Keep these things in mind, won't you?
I know. Most boring start ever. But seriously, this will make more difference to your life than the Darcy-Weishbach Equation ever will. You'll start earning soonish. Just plonk away a teeny amount like 1000 a month into an RD or something. Do some compound interest calculations and (to use 2014 lingo), what happens next will astonish you.
No, really, you idiot. Stop hogging at Thrissur AFC and get a good mutual fund instead.
You stay in freakin' Kerala. Most people around the world would do anything to be where you are (no, not in the hostel exactly - but you get my point). Tons of your batchmates go on bike rides. Join them. That way, you won't be spending your 30th birthday wondering how to pack all that you want to do in 5 days of an upcoming Kerala trip. Just... Go. Discover. Do. Click. Soak it in.
Write and draw.
You used to draw some decent comics when you were in school. You stopped while at college. Don't. Keep drawing. Soon, the internet will allow you to publish stuff online. Write. Write a lot. Regularly. That way, some of the stuff you do publicly online later will be less embarrassing. And trust me - there's a lot of rubbish out there with your name on it.
Listen to a lot of music.
You're stuck in a rut of listening to the same 30 songs over and over again. Explore new genres. Rock, metal, prog, classic, world, Mallu film... There's so much to listen to, and when you're 30, you'll feel like you wasted your 20s not listening to at least 1 TB by now. (Haha, you don't know what a TB is... How cute. Wiki it. Oh wait.)
Make music. Even if it's bad.
Soon, you'll be in a place which has talented musicians, a recording studio, a captive audience and tons of free time. Take advantage of all of that. Play stuff. Record. You'll never get that opportunity again. Going to MICA and not making music is like going to Barbeque Nation and eating paneer. Just publish something to call your own.
Value free time.
Treasure every free minute. And dammit, do something. You while away way too much time. Get off your arse. Exercise. Lose that flab. Go for a walk. Explore the cities you've stayed in but know jack about. Do anything. Just don't laze around. You gotta look back at each day and say, "Yeah, I did something awesome today."
Do this and you'll be fine. I wonder if my 40-year-old self would be kind enough to send me a letter, now...
Your just-turned-30 self.