Maybe you remember when, thanks to The Wall Street Journal, everyone thought the SEC was going to meet on May 7th to decide whether or not Ethereum (ETH) was a security. If you had taken up a large position in ETH prior to the 7th, you would have been disappointed when the price fell from ~$793 USD to ~$743 USD amidst news that there actually was no meeting after all.
The fight over whether bitcoin’s currency code should be BTC or XBT is ongoing (as of November 2017). When bitcoin was first introduced, BTC became both the abbreviation for bitcoin and its currency code. As bitcoin gained momentum and recognition, a large portion of the community asked for a better currency code that adheres to the International Standards Organization’s rules on cryptocurrency codes, mainly that currencies not associated with a specific country should start with the letter X, hence XBT.
A beginner might prefer to trade cryptocurrency stocks on the stock market (GBTC is a trust that owns Bitcoin and sells shares of it; trading this avoids you having to trade cryptocurrency directly). The main Bitcoin stock here in 2018 is GBTC. Be aware that GBTC trades at a premium (meaning bitcoins are cheaper than buying shares of the GBTC trust), which isn’t ideal. Also, cryptocurrency trading is a 24-hour market, where the traditional stock market is not. Learn more about the GBTC Bitcoin Trust and the related pros and cons before you invest.
The crypto world is a uniquely perfect environment for arbitrage. As William Belk argues here, the combination of it’s distributed nature, regulation, security, availability, and anonymity factors means that the marketplace has many inefficiencies, and that “arbitrage opportunities will continue indefinitely.” For example, some markets pay a premium for security, geographical location, or simply because they don’t know they can get it cheaper somewhere else. In some cases, the price discrepancies across different exchanges can be as much as 43%.

Limits orders allow us to place an order at a specific price. We can specify the amount of coin that we want to buy or sell, at the price that we want this to happen at. You may have noticed that the order book is always full of sell orders that are a little higher than the current price and buy orders that are a little lower. The advantage with limit orders is that we can do do the same with our orders. The disadvantage is that our transaction likely will not be filled immediately and will count on the market price to make its way towards us.

Cryptocurrencies are not all the same. Some are mined while others are created all at once and slowly released into the market. Some cryptos earn a type of interest when owned and some are tokens used by innovative development networks/platforms. Other considerations like the maximum supply of a cryptocurrency, alternative uses (other than being an exchange medium), can greatly influence its future performance.
EDIT: #10 Bonus (Suggested by @kerstenwirth ) — always check the ticker symbol. Ticker symbols are not universal, and may vary from exchange to exchange in rare cases. Those cases, though, can come back to bite you. For example, Bitcoin Cash trades on some exchanges as BCH, while it trades on others as BCC. BCC is also the ticker symbol for BitConnect, which was recently outted as a Ponzi Scheme. If you bought BCC under the impression was Bitcoin Cash, you would’ve lost a lot of money.
Figure out if you want to go long or short. Are you going short with every penny you have to invest, or are you going to go long with some and short with some? Long-term investors will pay a lower tax rate if they can hold for over 12 months, but as a trade-off, they WILL have to sit through corrections (likely seeing their balance go down 50% plus on paper as often as they see it go up). Short-term investors can avoid corrections if they are nimble, but they’ll owe taxes on the profits from each trade they do along the way (see: how taxes work with cryptocurrency to understand how the long term and short term capital gains tax work with cryptocurrency).
Categorize your investments and look at the long picture. In the process of your research, you’ll eventually realize you’re coming across a few different categories of coins. For some of them, you believe they have good teams, great vision, amazing publicity and a track record for successful execution. Great! Put these into medium or long-term holds and let them marinate into a delicious tenderloin. When the price dips, don’t even consider panic selling because anything in your medium or long-term portfolio should remain untouched for a set amount of time. BNB is a good example of a coin Miles considers a long hold. Recently, it dipped 20% for a while, and within our community, we witnessed some sell-offs to preserve investments. A week later, it jumped up almost 3x for a period of time.