I am a college student looking to make a buck every once in a while trading crypto (mainly BTC). My portfolio is $500 of my savings so nothing big really. This is like a pilot project where I get to learn what is what and see if I can trade. I am considering going full time during summers and hopefully after finishing college if summers will have spared me. The question I am constantly facing is, how do you know when you should (or have to) sell? When the price is rising, I don't want to sell because... greed tbh. But again when the price is dropping, I don't wanna sell either... sometimes the price might be lower than when I bought. In general, I am bullish that the price will eventually rise and I will make a killing, so no need to hurry. But again, I don't want to be a hodler; I want to be a trader. How do you guys know when to sell?
Trading actually is quite different from what you have pictured in your brain. Day trading is 99% done with leveraged options. Judging by your post it is obvious you don't know that traders don't buy and sell, but they bet on the price going up or down. This is going long or going short.
Since you don't know what shorting is, you have a lot to learn. Try making a test account in some of the trading sites that allow this just to find out the options available.