Most of these services offer some form of free portfolio tracking - this enables you to create a portfolio and track it properly to see how you do with no money on the line. This used to be known as paper trading in the 'good old days' before 2001. This kind of exercise can be a good way to learn and play around with things without being either serious or costly.
In the professional world, one of the key concepts is diversification. Harry Markowitz is a Nobel prize winning economist and one of his major discoveries was that adding new asset classes can dramatically alter the overall risk profile of a portfolio. His finding was that a portfolio that contained very low risk assets would normally benefit from lower volatility and higher returns if a higher risk asset was added. This is due to the likely lack of correlation between high and low risk asset classes.
Before making your first investment, take the time to learn the basics about the stock market and the individual securities composing the market. There is an old adage: It is not a stock market, but a market of stocks. Unless you are purchasing an exchange traded fund (ETF), your focus will be upon individual securities, rather than the market as a whole. There are few times when every stock moves in the same direction; even when the averages fall by 100 points or more, the securities of some companies will go higher in price.
Network effects -- In simple terms, a network effect occurs as more people use a service or product, and the product or service itself becomes more valuable and desirable as a result. Think of companies like Facebook (NASDAQ:FB). As more and more people join Facebook, it becomes more difficult for people not to use the platform in their daily lives.
The idea of perception is important, especially in investing. As you gain more knowledge about investments – for example, how stocks are bought and sold, how much volatility (price change) is usually present, and the difficulty or ease of liquidating an investment – you are likely to consider stock investments to have less risk than you thought before making your first purchase. As a consequence, your anxiety when investing is less intense, even though your risk tolerance remains unchanged because your perception of the risk has evolved.
The stock market is made up of exchanges, like the New York Stock Exchange and the Nasdaq. Stocks are listed on a specific exchange, which brings buyers and sellers together and acts as a market for the shares of those stocks. The exchange tracks the supply and demand — and directly related, the price — of each stock. (Need to back up a bit? Read our explainer about stocks.)

Some scammers will buy up a ton of some near-bankrupt, almost lifeless penny stock, then use lies and exaggerations to push the share price much higher. They might say the company is about to get some huge business deal with Google or their neighbor just struck gold in their similar mine, or they are going to land a major FDA clearance. That typically helps increase the value of the penny stock, which creates a profit for the promoter or scam artist. As the shares increase in value, they sell their holdings. These shares usually collapse back down to near-worthless status once the promoter has taken their profits and moved on. 

If the strategy is within your risk limit, then testing begins. Manually go through historical charts to find your entries, noting whether your stop loss or target would have been hit. Paper trade in this way for at least 50 to 100 trades, noting whether the strategy was profitable and if it meets your expectations. If it does, proceed to trading the strategy in a demo account in real time. If it's profitable over the course of two months or more in a simulated environment, proceed with day trading the strategy with real capital. If the strategy isn't profitable, start over.

In addition to knowledge of basic trading procedures, day traders need to keep up on the latest stock market news and events that affect stocks—the Fed's interest rate plans, the economic outlook, etc. So do your homework. Make a wish list of stocks you'd like to trade and keep yourself informed about the selected companies and general markets. Scan business news and visit reliable financial websites. 
When thinking about a stock exchange it is worth remembering that it is a capital market. The primary purpose of a capital market is to enable businesses to raise money to provide working capital to fund expansion and growth. In exchange for this money, the companies issue equity in the form of stock, creating stockholders. Each stockholder ownes a piece of the active business relative to the amount of money they invested.
Why I’m buying: Spell out what you find attractive about the company and the opportunity you see for the future. What are your expectations? What metrics matter most and what milestones will you use to judge the company’s progress? Catalog the potential pitfalls and mark which ones would be game-changers and which would be signs of a temporary setback.