Bitcoin (BTC) has been engaged in a predictable up and down pattern where it absolutely crashes at the beginning of any year and then sky-rockets as the year nears its end. Bitcoin held steady at around $19,000 in December 2017, and then sure enough – crashed big time to around $6,000 at the beginning of 2018. At the time of writing, March 8th 2018, the price of Bitcoin is relatively stable between $10,000 and $12,000. In my opinion, the price will run again soon.
We've had splits in the technical community before. Two years ago, Angular was the dominant Javascript framework and React was new with a small following. Angular's community split between Angular 1 and 2. Today, there are 236,472 repo's associated with React compared 247,335 for both angular variants. Alone, interest in react is about to supercede both variants of Angular combined.
The second reason to buy the most liquid coins is that there are risks of scams. When you purchase Bitcoin you are sure that you will be able to sell it to somebody later. However, when you buy X coin, which is not as liquid and as popular as Bitcoin is, your risks are higher as everything depends in this case on the project, its team, goals, roadmap, background etc.
There are lots of studies about emotion in trading. Fear of missing out, greed, etc. are very common causes for people to make mistakes while trading. No matter how experienced you are, you will eventually be led by emotions and this might make you lose money, so you have to prepare yourself to do it as little as possible and to control yourself better or you will lose more than win.

Investing and especially trading, is a highly skilled task. You need the best equipment, execution and tools. When the market is only going up any fool can make money but that blessed state never lasts long and what is left is an environment requiring focus, skill and discipline. To succeed unlike the devastated cohorts of dotcom and the real estate bubble, you have to work hard at it.
Only invest what you can lose. During the recent crash in January 2018, hobby-investors got burned. Reports of frustration and losses came at the cost of broken monitors, smashed laptops, and heavy monetary losses. While the rules are in more particular order of importance, it’s safe to assume that this is the most important rule, the rule to rule the rules. As soon as your money is converted into cryptocurrency, consider it lost forever. There is absolutely no guarantee you can get it back. Losses don’t simply come from dips in the market; extraordinary factors such as hacks, bugs, and government regulation can mean you’ll never see any of your money again. If you are investing money you can’t afford to lose, you need to take a step back and re-evaluate your current financial situation, because what you’re about to do is an act of desperation. This includes: using credit cards, taking out mortgages, applying for loans, or selling everything and traveling the world (as glamorous as that sounds).