It's not easy, such profit is usually made with high-risk operations, like trading/holding altcoins.
Best way to tranform 2 btc into 4 is to put everything on primedice xD
You'll have nearly 50%chance to win what you want!
It can be result into lose and bye bye bitcoin. you will regret if you do this.. better to invest that amount of bitcoin into trading but first better to learn first how to trade and choose top 10 altcoin in coin marketcap that you can choose like dogecoin litecoin monero ethereum just hold it if you see the price increase 10% each just sell it and buy again if the price of those altcoin is low