Take profits. Some investors think “taking profits” is a dirty phrase, but it is a rather conservative strategy none-the-less. Taking profits can result in you making less money than you would have if you did nothing and just “let it ride”… but that is only true if Bitcoin goes up over the long term. If you have hefty profits, consider taking them off the table, and then waiting for a lower price in the future. Worst case, you can buy back in at a higher price later (leaving some potential profits on the table). TIP: If a coin just went up 400%… consider taking some profits. Cryptocurrency almost always corrects at some point after a big run. I personally would say HODLing after making 400% gains is called GREED. I won’t ever sell my full stack in one chunk, but I’m going to start averaging out when the MACD turns bearish after a 400% – 1,000% run if the run was somewhat organic. If the run was the result of a pump and dump, then I will likely take it all off the table quickly. Pump and dumps are frustrating events, like I said, watch out for manipulation.

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.
If you are doing any active trading, set stop losses. For any coins not in your medium or long-term holds, always set stop losses. This is important for several reasons — the most obvious is mitigating your losses. But more importantly, you force yourself to decide on a point of acceptable loss, and because you now have a reference point, you are able to measure your effectiveness to keep or adjust for future trades. Sometimes, during a market dip, altcoins can plummet, and stop losses can lead to profitability by automatically selling for fiat that you can use to re-enter at lower prices.

No, the successful trader is not me. I’ve gotten lucky a few times and I’m still refining and trying out strategies; on the other hand, I’m part of communities of people who trade on a daily basis to grow their portfolios, and while some of the results can be attributed to luck, a majority of it is based on fundamentals, good habits, and experience.