the first and most important advice would be portfolio diversification, don`t put your eggs in one basket, split your portfolio in 3 so you have 1/3 for long term investing, 1/3 for medium term or swing trading and the last 1/3 for short term investment or margin scalping
Ups and downs will always be a normal thing in every market and there is no way anyone can absolutely avoid it. As it is, the best thing to always do is to know where you are buying any market and when you are selling, if you want to take advantage of those fluctuations. It is not only about diversifying, but where you are diversifying into, how you are going about the decision making process when it comes to buying into a market and so many other things, is what is necessary to always take note of.
these is ups and downs in the market price of some crypto coins in which the first one is Bitcoin and then next are Ethereum Litecoin and few more but you will see more unstable prices of Bitcoin and Ethereum as these two are also favorable for long term so one can sell for profit whenever he feels that he is in profit.
Market fluctuations are a normal part of a market and it is these fluctuations that traders take advantage of every day. Now I would not say this should be a difficulty as no one wants to trade a stable market anyway and it is the volatility that makes the trade even more interesting, but as long as you have the knowledge to always make best market decisions, difficulties when it comes to trading should never be a thing at all for such a person. The reason a lot of people face difficulties is because they want to trade but refused to learn.
