I would tell my 22 years old to save as much as possible and live with a roommate or your parent, if possible.
+1
As I mentioned in your other thread, slash every cost you can (while not being crazy about it). I lived with my parents until age 32. Sure, it wasn't the easiest thing to mention to prospective women - but the type of woman I was looking for would understand my motivation for living at home as being pure financial. In fact, I dated 2 women who were also living at home at the time, also for purely financial reasons.
Living at home can help sock away $7,200/year (minimum). And that's after-taxes.
Also, learn about the tax code as you get older and your income grows. For instance, you should study up on the health insurance policies available to you.
In my case, I have very cheap individual health insurance with a High Deductible, and I qualify for a Health Savings Account. It's like an IRA except for medical expenses, and I get to roll over unused funds year after year in my own account that I own. For every $1 you put into an HSA, you reduce your taxable income by $1, AND the earnings will grow tax-free as long as you use the funds for healthcare expenses. If you don't use them up, you can simply withdraw them at age 65 or 67 and pay income taxes on it like an IRA.
The great thing is that - depending on your health insurance policy rates - the tax write off can pay for it. For instance, I max my HSA each year - about $3,200 contribution, which gives me about a $1,000 savings in income taxes. My current health insurance policy only costs me $650/year, so my HSA tax deduction pays me $400/year for my high deductible plan! Of course, my deductible of $5,500 means I pay for the first $5,500 in health expenses each year if I get sick, but I'm very healthy, and odds are I won't have any significant expenses for quite a while. By the time I do, all of those years of contributions will be more than enough to pay for anything.
But don't forget that you can be on your parent's health insurance plan up until (I think) age 25 or 26 for free. See if you can qualify for that.
Also, in your income tax rate, learn about the Saver's Credit. It gives you an additional income tax credit if you save in a 401k or IRA and your taxable income is low.
Saver
It may not be huge, but getting an extra, say, $350 in your pocket from the saver's credit, and a few hundred $ in your pocket from an HSA account tax deduction, coupled with living at home and slashing other expenses can really snowball into huge increases in your investment portfolio in just 10 years!
And another thing - don't forget to look at the total cost of owning things. Buying a more expensive new car vs a more modest new car is not only more expensive for the sticker price, but then you most likely will pay more for insurance, property taxes, and possibly even after-market parts (like speed-rated tires, etc.). Just so complete strangers on the road whom you are next to for 10 seconds and whom you will never see again are impressed by your Mustang or some other hot rod.
If you have $3MM in your portfolio and can easily afford to drop $50k on a sports car, then go do it. But burning up the cash in your 20s/30s will make it forever disappear, and it will never have a chance to give you economic freedom when you're in your 40s and 50s that everyone else can only dream about if they hit the lottery.
Don't be afraid to buy used furniture and other items on Craigslist (but by all means, wipe any furniture down with a bleach or other cleaning solution that won't stain or damage it). It's crazy what new DISPOSABLE furniture costs in the store - even at WalMart! Compare that to much cheaper and halfway decent furniture that's 20-60+ years old (back when furniture wasn't disposable) and will last you another 10-30 years with decent care. I spent perhaps $3,500 on furniture between Craigslist and a discount furniture store and a warehouse clearance sale to outfit my 1,700 sq ft house with 2 bedroom sets, an office, and dining room/living/family room furniture....and that's including $1,400 for my new master bedroom set from a furniture store (I could have spent $1,000 less if I searched longer on CL for a used master bedroom set). $3,500 is less than many spend on just a single bedroom set, much less an entire house!