Keep a critical perspective on the data that exchanges are providing you: technical analysis is only as good as the data it’s analyzing. When looking at volume numbers, for example, ask yourself: What’s the source of this information? Has it been validated? Could other factors be skewing the number? Beyond just looking at the numbers, it’s important to understand the meaning of those numbers: what they imply, and what biases could be influencing them.
There are some people who believe that Bitcoin is the only blockchain based protocol which has value and that all others will fail. These people are known as Bitcoin maximalists and their belief is based on economics, specifically Austrian economics, and that the technology which is great for Bitcoin is not useful for anything else. I am more open minded and believe that there are other applications of the technology which will create sustainable ecosystems but I could be proved wrong here. It is important to spend time doing your own research and building up your own view on where the technology may be used.
For example, there are cryptocurrencies, such as Litecoin, with the same goal as Bitcoin. In this case, it would be a good idea to compare its market capitalization with Bitcoin. This site ranks coins by market cap. Always be sure to check there when evaluating a new coin. If you notice a large shift in market cap on a certain date, it may be worth it to check for any news that day to see what may have caused it.
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.
The natural inclination for crypto investors is to identify a new altcoin with the potential for growth, invest heavily when it's still inexpensive to do so, and then reap the rewards when the value increases. That being said, the altcoin market is growing so quickly that many new digital currencies hitting the market might not be good long-term investments.
Common sense doesn't apply for some traders. In October, Spatafora started trading bitcoin, litecoin and ethereum to learn about the market and understand whether any of the coins were undervalued. Instead, he found that many of the investors exhibited irrational exuberance in believing the virtual currencies would never stop their climb in the market.