Investing is buying and selling at the right time. Don't buy coins when you are bullish because you will experience losses if you are trapped at a high price. It's best to always monitor market movements and read news about crypto. because bad news will make the market experience a correction. and do research before buying coins, especially if you buy coins that are not well-known, not top coins.
It's not even wise to buy coin that doesn't have any reputation especially buying them at the peak there would be some forces to drive down the market making the investors who invested at the top regret. It's always advisable to buy coin that are known let's take for instance bitcoin, ethereum, BNB or solana that are well known with these coin it would be very hard to lose money even though their percentage drop it would be very small or minimal and quickly it would regain back it market position again.
When it comes to holding of coins I will advise we focus on Bitcoin, from history Bitcoin has proven to be the coin in the world and should be taken seriously, Bitcoin is the oldest coin in the world and the Best coin, other coins growth are determined by the growth of Bitcoin and therefore anyone planning on holding coin for a very long time should do it with Bitcoin so has not to lose money.
Bitcoin is a peace of mind investment in Bitcoin you don't have to fear losing your money, so if you can hold coin for a long time the best coin to do that with is Bitcoin, those who has been investing in Bitcoin for years now are benefiting from holding Bitcoin for long, in Bitcoin investment all you need to succeed in patience.
Some new coins that you see every are not worth buying and holding for long, I have a friend that refused to invest in Bitcoin because he believes Bitcoin won't increase quick the way he wants, so he decided to invest in all this new coins so he bought and started holding before we knew it the value of that coin fell and till now the coin is forgotten that the value is still very down and that was how he lost his money.
A lot of all this new coins are scam and should not be something or coin you should be holding if you don't want to waste or time and money.