Everyone needs a plan when they are in the market of cryptocurrencies, if you do not have one then you are going to find yourself on situations you could not foresee and just when you need it the most you will get something called paralysis by analysis.
This happens when people receive too much information at the same time and instead of taking a decision they keep delaying taking the decision so they can gather even more information, however if you have a plan you can take decisions in a split of a second and that is critical when it comes to the markets.
Planning when to buy, at what price, and when to sell, at what price is the first step to becoming a good trader. You need to know when it drops to x price it means this and that is when you should buy and afterwards when it goes up to Y then it means this and you should sell and all of that even before you trade a single satoshi worth. In order to do something like that, you also need to know about trading and study it a lot because that is how you learn what prices are good, it is not just gut feeling, it should mean something.
Resistance and support levels are very important in this case, if you could buy right at the support level then it could bounce back from there, if it goes down even more and break under support then you can buy at the next support, and same goes for selling at the resistance level as well piece by piece instead of all at once.