The use of borrowed money “levers” or exaggerates the result of price movement. Suppose the stock moves to \$200 a share and you sell it. If you had used your own money exclusively, your return would be 100% on your investment [(\$20,000 -\$10,000)/\$10,000]. If you had borrowed \$5,000 to buy the stock and sold at \$200 per share, your return would be 300 % [(20,000-\$5,000)/\$5,000] after repaying the \$5,000 loan and excluding the cost of interest paid to the broker.

# Portfolio managers are professionals who invest portfolios, or collections of securities, for clients. These managers get recommendations from analysts and make the buy or sell decisions for the portfolio. Mutual fund companies, hedge funds, and pension plans use portfolio managers to make decisions and set the investment strategies for the money they hold.

Those exchanges allow the purchase of cryptocurrency either via a card payment, or via a wire transfer / SEPA deposit from your bank account. They will also require some sort of identification because they are bound by financial laws related to customer due diligence and AML (anti money laundering) legislation. You may be asked to provide identification information such as an ID card, a passport or a proof of address. Note that some sites have different thresholds to buy cryptocurrency or withdraw fiat currency to your bank account based on the level of identification info you have provided. If you are into this seriously, make sure to provide the info necessary to the level you want to reach in time, not at the last minute when you want to liquidate your positions (or said differently, when you want to cash out).
To make comparisons between companies, sectors and markets a little easier, there are a number of mathematical models used. The most common and often the most helpful is the P/E ratio. The Price to Earnings ratio takes the share price and is divided by the earnings per share. It is possible to calculate this using past earnings, projected future earnings and with all sorts of moving averages ;-) Therefore, this is one number that it is vital for any investor to know and understand.
Should the company management and majority owners choose, they can pay one or more dividends per year to stockholders. The money for these dividends will typically come from profits earned within the business. In most countries, these dividends are subject to income tax payable by the receiver. Often there is a withholding tax taken at source to ensure that non-resident shareholders pay as well.
Regarding your private keys, can either keep them on a software wallet, or on a hardware wallet. The software wallet is the easiest way for beginners, but it implies that you have a computer that is properly secured (strong password, antivirus etc.) and that you do backups of your data. Remember, if you lose your private keys, the money is gone forever. As you get into cryptocurrencies more seriously, you will inevitably look for a hardware wallet, which is a dedicated device resistant to hacking where you can store your private keys (or to say it in an easy way, your crypto assets/invested money). I have already written an article on a hardware wallet, the TREZOR (see here). The most common wallets are the TREZOR and the Ledger Nano S. The TREZOR has a new model being sold from January 2018 (Model T) which will support much more currencies than the current TREZOR. The Ledger Nano S has more integrations currently, but I would recommend to wait for the TREZOR T to judge properly. Those devices usually cost around 100 USD, so once you have more than 100 USD to protect it starts making sense to get one.
Finally, keep in mind that if trading on margin—which means you're borrowing your investment funds from a brokerage firm (and bear in mind that margin requirements for day trading are high)—you're far more vulnerable to sharp price movements. Margin helps to amplify the trading results not just of profits, but of losses as well if a trade goes against you. Therefore, using stop losses is crucial when day trading on margin.
Buy in thirds: Like dollar-cost averaging, “buying in thirds” helps you avoid the morale-crushing experience of bumpy results right out of the gate. Divide the amount you want to invest by three and then, as the name implies, pick three separate points to buy shares. These can be at regular intervals (e.g., monthly or quarterly) or based on performance or company events. For example, you might buy shares before a product is released and put the next third of your money into play if it’s a hit — or divert the remaining money elsewhere if it’s not.