The technique itself is simple. You invest, you wait for a favorable time and you bring it out. If you want a long-term investment, wait until this coin is legalized in any country. Then the price grows.
the ways you mentioned can be tried. and my advice, find a coin that has a high value for greater profit percentage and manage your investment well in order to succeed.
Let alone the benefits in the world of crypto always have risks, so seriously consider buying a basket of cryptos such as like the CombiCoin that belongs to the best possible ICO (r post undiscalued ico token.) It involves a lot of reading and research - and perhaps the most important part - do your own due diligence.