The best thing a young adult can do is two-fold. First, invest time and effort in becoming financially savvy. Second, open a Roth IRA and invest as much as you can as early as you can.

The Roth IRA does not provide any immediate tax benefits, but when you are young (high-school and college age for example) your tax rate is probably the lowest it will be in your wage-earning lifetime. Thus, you can earn enough to fully fund a Roth IRA with little or no tax liability. Then, that money grows tax free until your retirement. Upon retirement you can withdraw the money including all those decades of compound returns completely tax free. The Roth IRA is as close as you can come to making a fortune legally tax-free.

Another Roth IRA advantage is that after it has been open for at least 5 years you can withdraw any amounts you put in (but not the earnings) tax-free and penalty-free. This would be a bad move for your retirement funds, but not as bad as trying to do the same from a conventional IRA.

As for what to invest inside the Roth, that depends on your appetite for risk. Personally I prefer mutual funds, but if you have the time, inclination, and knack for it, you may well do better in individual stocks.

Your early start and interest bode well for your financial future. Good luck.

The best thing a young adult can do for his/her financial future is to “invest” on knowledge that enables him : (in order of importance)
1. to get a good job or good startup : for future income
2. to get financial return for investment
3. to have good health

“Gamble win” in stock may not be sustainable. Money won may be “easy comes, easy goes”.
If you have investment knowledge that enables you to pick undervalued great stock, you should do it on your own, otherwise look for IRA-typed funds or index funds or ETFs that have low management fees. In either cases, the “Asset under Management” is too small to matter much compared to getting knowledge for you to get a great job, startup or investment successfully.

If you are going into investment or finance, I have compiled some resources in this best answer of mine on:

the best way to learn about investing

Course guidelines of finance, investment professional certifications like CFA, CFP, FRM, CAIA will give a rough idea of what to learn in various aspects of investing. There are many free online courses too.

Another aspect for financial future will be knowledge on health as health is wealth.
Healthcare cost is a big chunk in senior life. Prevention is better than cure.
The money earned/won means nothing when you have bad health.

Some examples of things to learn about health are:
healthy lifestyle, exercise, diet, prevention of diseases etc…

Hope this helps.

Depending on how "young" you are, you should be able to assume quite a bit of risk in what the finance world calls your "portfolio." Now, depending on how risky you want to be and how much money you (reasonably) expect to make in your career, you can continue to invest in stocks, or switch to what are traditionally safer or more secure investments.

No matter what your age, if you have no current retirement savings, I would personaly suggest that you invest immediately in an IRA. The more you save early in your career, the more you will have when retirement time rolls around. (Remember, retirement accounts accrue interest and you earn money on the interest accrued the year before...so if you invest now to retire in 30 years, the money will grow a lot more than if you invested the same amount 10 years from now.) The government limits your contributions to IRAs and other retirement accounts, so if you're making more money than you need to live, then you should always try to max these out.

Now, If you have retirement savings invested and are continually contributing to those accounts, then investments are the way to go. This is because these have unlimited earning potential, plus you can get the money out for any reason at all. Again, if you are young and looking to start a family, buy a home, or make another big investment toward your financial stability, stocks are a much more fluid choice. Stocks, though, change in value daily, so you can never really count on that money until you withdraw the funds from the investment account.

Either way, I wish you luck on your investments. The most important thing about solid financial decisions is to do your research. ALWAYS move with caution if a financial institution wants to charge you fees. Many are valid, but some are outrageous. When investing, look at the stability of the company controlling the funds and remember, if it looks too good to be true...then it is!

Congratulations on making some sound investments already. Many people in today's market would kill for the return you have already had. If you like to gamble, stay where you are. Apple has done well for quite awhile. If you're like me and you are averse to risk, switch to something with less risk and more stability for your long-term financial future.

Apple is an excellent investment right now, as they continue to improve
their Mac series. My neighbor has five Ph.D in computer technology and
he says Mac is the best thing on the market today. He does not work for
Mac, he was suggesting I purchase one. I would venture to say this is
Not the time to pull out of Apple.

You might even consider re-investing in Apple as it grows with Mac
I would and do follow Apple's trends very closely right now. A very wise
man once said; "To he who has much...more is given" (energy gathers energy) and when a company has a good cash-flow they usually continue on
the upward trend for several years. I'd watch them close & not run off!

Several financial magazines have been reporting for too-many-years that only a very small percentage of Americans have any kind of a serious
savings account. This means a large percentage of Americans exist one
paycheck away from disaster. Small children should be taught to keep a
'passbook savings account' at a bank, and kids in high school and college
should have substantial savings to invest. They don't. It's one of the
reasons that America is facing a serious economic crisis today

I think it was Roosevelt, who said "Nothing can take the place of
persistance, talent will not, there are many poor men with talent" It
takes persistance and dedication to build a financial portfolio to see
a young person into marraige, family a real home and more than one car

Americans were swindled into a lot of 'get rich quick' scams. One of the
worst was Real Estate. Buying fire traps and covering them over with
siding; to rent to the poor. Millions of dollars was lost in Insurance and lawsuits. As well as several poor children burned alive in agony.
If it's true that you reap what you sow. America did not reap success

The Wall Street Journal reports that 92% of American jobs listed 20 years
ago were forced buy outs by Japan. 92% that is chilling. And contrary to
popular belief; it is Not huge corporations which supply the largest
percentage of jobs, but private business owners. When these thousands of
small business owners were forced out, none had 'Unemployment Insurance'
for themselves. Meaning tens-thousands were never part of AFLCIO 'reports
So there really are no accurate "unemployment figures" It will be up to today's youth to reinvest in their own nation's business projects. Do Both. Continue to invest in American business...so America & your own RA
One to support your immediate cash flow..other cash flow in a strong USA

All the answers above are great. I would ad that the first best thing to do is discipline yourself to save 20% of the gross of everything you make. From the git-go just force yourself to live on 80% of what you make. Save 20% all your working life and you will retire in your 50s with a million+ (if you're even 1/2 savvy at investing).