HODL is always the best investment method, I still say that.
I think Holding your cryptos will be the best thing you have to do for many years. You can really become rich in few months/years. Just be patient.
I don't think holding is working at all. Nowadays investors are simply buying and holding bitcoin for a short period and when they believe that they have made enough profits they go on to sell. The period for which they hold their crypto normally lasts for about 2-4 weeks.