The basic
The most basic rule of investing is to buy low and sell high. That seems obvious but most people don't do that. It is like the other away around. Buy high and sell low and then they wonder why they are not making any money. You should always when people are selling and sell when people are buying. An example is the 2008 crash. A lot of people were selling their investment. A few brought investment and those that brought, became millionaire. If you ever see a good stock doing bad, buy and then wait for it to go up and then sell. Also don't hold on too long. Look out for sign for when the investment will go down. Also just because it crashed doesn't mean you should buy. An example would be bitconnect. The reputation of bitconnect is ruined and will never go to the level it once was at. If apple's stock goes down (if they do nothing dumb) then buy and it will eventually go up. You should decide if it is wise to invest. Also the best investment is an investment in you. Research. Read. Feed your mind with knowledge. Watch the video down below to learn more.