My way of investing coins

Well, I know it is very risky to sell a lot to get the gap profit such as you buy at the price of 2000 and if it goes down, you can sell it at 2000 and buy again at the price of 1000 for instance then you can increase your coins by double!
This is the best scenario, but in my personal experience, it is pretty tough. Since we cannot fully protect and sometimes the market changes crazy fast even more than our fingers haha.
So Here is what I do.
about 80 ~ 90 percent of my coins are never touched, they are in the paper wallet somewhere in this universe (hopefully I can find it and not forget where...).
With the remaining 10 ~ 20 percent I do the sell and buy back when the price decreases.
And here is the thing, I do not sell all out of them.
let's say the 10 percent of the coins costs 100 dollars. Then even if it increased or sth, I sell only 100 dollars and buy when the coin price is cheap. Also, This way, I can keep collecting more coins but not lose much outta my greed.

I find this very beneficial since it is not big portion of my coins so I can easily play around without much pressure, inducing actually a lot better decision making and less regret! It is because majority of my assets are invested solid.

You can share your own tactic or strategy with me~!