If you are going long, consider building an average position (for example via dollar cost averaging or value averaging). There is no better way to avoid making a poorly timed trade than buying incrementally instead of all at once and thereby buying an asset at its “average” price over time. If you don’t have a really solid grasp of technical indicators and the way the volatile crypto markets work, consider averaging out of positions as well. Averaging isn’t just financially conservative, it is important psychologically. Taking too big of a position at once can be emotionally difficult to deal with (and can thus lead to bad decision making) given the historic volatility of the cryptocurrency market.
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.
This is not a get rich quick scheme. While returns can be good at times, I have seen periods of stagnation, five +30% market dips and a bear market. Whenever you enter the market, it could be on the rise, in a drop or be stagnating. I have also had days and weeks where I have seen a significant decline in my portfolio. I can't predict what the market will do when you enter. Please invest for the long term. This is much more volatile and risky than the stock market.
Many governments are unsure of what to class cryptocurrencies as, currency or property. The U.S in 2014 introduced cryptocurrency trading rules that mean digital currencies will fall under the umbrella of property. Traders will then be classed as investors and will have to conform to complex reporting requirements. Details of which can be found by heading to the IRS notice 2014-21.

Volumes indicate the liquidity of an asset. The greater the liquidity the easier it is to buy and sell, even when there is turmoil, and the lower the Bid-Offer spread and therefore the cost of trading. You want to avoid assets with tiny liquidity as when the shit hits the fan it will be costly to exit. Bitcoin has world-class liquidity. I run a crypoasset analysis site named Blocklink.info. Here is a screen-grab of the most liquid assets in the world.

Don’t be greedy. No one ever lost money taking a profit. As a coin begins to grow, the greed inside us grows along with it. If a coin increases by 30%, why not consider taking profit? Even if goals are set to 40% or 50%, you should at least pull out some of the profit on the way up in case a coin doesn’t reach the goal. If you wait too long or try to get out at a higher point, you risk losing profit you already earned or even turning that profit into a loss. Get into the habit of taking profits and scouting for re-entry if you want to continue reaping potential profits.