Read!
There are hundreds of books on the topic. Most usually cover much of the same ground. If you don’t have lots of cash on hand, and even if you do, you should practice for a while (6 mos + of daily attention at least!) without spending a nickel by “paper trading”. Trading only on paper with no $$ involved. Think of it like a fantasy foot ball league. You select certain stocks and set up tracking mechanisms that make sense and work for you (each book tends to offer dozens of methods) and then you follow the “life” of a proposed trade. If you would have made money your balance sheet will reflect that. If you would have lost money you should have plenty of data to learn from so as not to duplicate mistakes when using cash, bucks, green backs, dinero, moolah, ducketts, scrillage, or lettuce for the kitty. 
Learn the differences among all (or at least a good chunk of) the investment vehicles out there. Some have distinct advantages over others depending on your personality type.
Are stocks your thing? Maybe bonds are better for you. Are you savvy enough about the economy to use either depending on market conditions? What about commodities trading? Precious metals, foreign currencies,… pork bellies and oranges?
Day Trading?
:roll:
What about Real Estate, or Tax Lien Certificates?
401Ks are great if you don’t have the discipline to sock money away regularly, but as you mention, they aren’t available with some jobs and as recent history has proven, don’t add up to much if a snake is at the helm of a company. Roth IRAs allow for TAX FREE growth (not tax deferred… Tax FREE) A Better option for ME. IMHO
Another tip of an ice burg… Tax shelters.
Look into them.
Fact- The average American will earn well over 1 million dollars durning their life. Why do so many people die penniless? It’s not what you earn, it’s what you keep.
Fact- The two largest debts that Americans pay on are #2-- their mortgage, and #1 - Taxes.
Find ways to reduce both and you will have much more to invest wisely.
What ever you do… take it as seriously as you would running and owning your own business. You wouldn’t start a venture on that scope without knowing a thing or two about the industry, would you?
It’s not difficult information, but there is a lot of it, and it can be pretty detailed. Spend some time with it. 
If you are only in it for the thrill of making a few quick bucks then you are just as well off driving to Reno and pulling the slots for a weekend.
Best of Luck!
Scott McCallister