Generally we want to learn from you. Its important we review the year and probably correct our mistakes in 2020.
Regards.
The thing that I did this 2019 is hold all of my coin as long as possible since some predictions is saying that the price of bitcoin will not gonna rise that much. But when the time that btc rises, I sell some of my coins and I forgot that I should have hold it longer. I forgot that halving is gonna happen soon and that is my biggest regrets after all.