if you have lots of money, it is good to hold bitcoin. but if you do not have money, it is better to grow bitcoin than just hold.
so when you grow and make a profit, you can save the most and hold for the long term.
Even if you have a lot of money but still it is better to keep them growing, if you dont want to risk them all then just do it with a half or just with a quarter of what you have, in that way if the price even drops in future you won't be in loss because you have been growing your bitcoins gradually with the time and if the price grows then you will earn a lot more profits then usual.
Holding is very simple, it just needs some patience, it is not necessary that you sell every time there is a price increase because that inrease could be more when you wait for a longer time, one should know how to have patience and treat his investment like a time deposit where there should be a definite time before you withdraw.
It is however smart to secure some profits from time to time. Just look at the peak of nearly $800 in June. I kept selling small parts of coins in the runup to that price, and I bought back when it went below $600 again. That's how you increase your coin count. I you just keep holding, then not much will happen beside you seeing the value of your coins go up or down. Action is what makes you get the best profits.