First off, MS is dying, closed source is dying, you are jumping on a sinking ship. IMO ASP.Net, Windows, basically anything MS makes, is all junk. Hugely bloated, overly complicated, non-intuitive, and they want tons of money for all of it.
I would highly recommend you look into the future at working on a LAMP stack. Open source is the new trend, free software, non-proprietary, and the greatest thing is, all this software makes sense, it works. When you go from MS environment to linux you are like, whoah, this is how computers were meant to be used. This actually makes sense. I don't have to memorize a bunch of arbitrary, long, cryptic commands to do things. If you ever check it out, you'll know what I'm talking about.
That being said, I can't stop you from wasting your life on garbage created by trash, it's your perogative. As for your question, YOU DONT NEED TO KNOW ANYTHING. Fake it til you make it is the key phrase here. Actually, works for all of life. But trust me, no matter how terrible you are, someone just hired a company in India or China to do a job and they are going to do 10x worse.
just start bidding jobs and lie through your teeth about how great you are and all the experience you have with this and that and how that's kind of outdated but you can still work with it, etc.. Basically Fake it til you make it. You will need to learn the gift of gab if you want to be successful at this. If you can't work people, then you need to hire a face man to handle your clients. Pay him 10% or less, never more. Also, if you screw up a job then just quit, don't accept payment, and you won't get a bad mark on your profile for it except that you cancelled the job. As long as the client doesn't have to pay and can hire someone else, they never complain. I've cancelled tons of jobs for various reasons.
Anyway, Most of my work comes from fixing the broken horrible code others have passed off as legit work. My consensus is that less than 1% of the entire freelance pool has any idea what they are doing, and most likely code drunk and blindfolded.
There is no way you could do a worse job because it's not possible to do a worse job. Just google google google, because for the first few years that's going to be your life anyway. I've been at it 10 years and I still google things every day. I hate google, but without them, I'd be lost.
Stack Overflow (and sister sites like super user, security, programming, etc.) are GREAT. Go on there and look for questions you can answer. If you don't know the answer off-hand, google it and try to find the answer and answer it. Don't worry about rep or if someone else gets in there before you. Think of this as something you are doing for yourself. Answering questions, believe it or not, is invaluable in building your knowledge, experience, and confidence. The community will help you realize when you have made an error or not used the best practice. Take this criticism as little nuggets of gold. I am 10X better programmer for being on SO and answering questions. It is invaluable. Not only that but sometimes you meet people who want to hire you. Then again, I will spend 8 hours fixing someones problem for them if need be, I refuse to give up. Several people have contacted me and hired me because of answers I've posted on SO. So do your best and to give great answers and don't worry about rep or all those haters that will give you a hard time. Just do your best and the rewards will come (along with a Stack Careers invite).
Stack Careers is one of the best job sites I have ever been on. Get on there immediately if they send you an invite.
Read Joel Spolsky's blog on software management. It's from the employer point of view mostly, but it gives you priceless insight into the industry, especially as a newcomer.
Other than that, just bid on jobs, lie a lot at first and pretend you know everything. (Everyone else does this too so don't feel bad). Build up your profile on whatever freelance sites you are getting leads on by taking tests, adding to your portfolio, etc.. while you are working and bidding jobs. Don't spend a bunch of time getting ready, just jump right in and start making money, that's the most important thing. Be super nice and do a great job so you'll get high ratings and good feedback from your clients.
Every job you complete, save it somewhere, put it on GITHUB, save it to a webserver, put it somewhere safe and start creating a portfolio of all your projects. Even if its just some small widget or some minor thing, put it in there. It doesn't have to be some big deal or huge project to be in your port, you just need content, as much as you can get at first so you don't look like a noob.
Also, as your coding, your going to have snippets of code you re-use. There are lots of different options, but in over 10 years, my favorite by far is GIST on GITHUB. The perfect solution for storing snippets. Use it.
Also, if you build a framework or any type of application, put it on GITHUB. Put as many projects as you can on there. Show potential employers your GITHUB page.
Create your own website, blog about technology, create useful programs and tools for people to use. Set up some services if you can think of a need or niche. Set up paypal or some kind of payment processor so you can start accepting payments from clients through your own website.
Just keep plugging away, building up your website, your blog, your portfolio, your profiles on various freelance sites, profile on any sites where you keep content like GITHUB or Behance.
And remember to raise your rate as you get better. I made the mistake at sticking at 20/hr for way too long. Then one day it occurred to me, wait a minute, I'm the boss, if I want a raise, I'll just give myself one and bumped it up to 50. I started landing way higher quality clients and making way more money eventually landing at around 80/hr. That's the highest I will go, but I move it down and back up again depending on how much work I have, how bad I need money, how chincy the freelance site I'm on is, how chincy the client seems, etc... But it sure is great to make like 1200 bucks in a day or two. :)
Anyway, to summarize...
Dump ASP and move to open source
Fake it til you make it
Quit any jobs you screw up on immediately
Go on SO and answer questions every day
Read Joel on Software
Bid and land jobs while building up your profile
Increase your rate as you get better (about every 3 - 6 months go up 5/hr)
Save all your successful projects in a portfolio for future clients
Create your own website, blog about technology, add useful tools
Create projects on sites like GITHUB, also put your snippets into GISTS
Sign up for Stack Careers if you get invited, lots of remote jobs
Just keep improving your skills, your online presence, etc..
You'll be making 6 figures before you know it.