The financial markets and trading offer the ability to earn huge profits and huge losses, risk-management and a responsible approach making sure that you truly understand everything you are doing is key to success in this fun, exciting and potentially very rewarding industry. Spend your time researching and learning as much as you can, learn about risk-management and try to always see what other people cannot - all these things motivates and develop me to remain in the trading.
That is not how you "develop stronger hands", that is how you become a good trader and yes a good trader does have a strong hands but you are talking about how to be a good trader skipping the stronger hands part. The way to builda strong hand is to force yourself to hold, I do not know how you would pick it but I just bought some bitcoins, put it on an USB and locked it in my banks vault, I had some things there anyway so I put the USB there.
That allowed me to not be able to sell whenever I want. That is the kind of forcing you need, find a way to not be able to sell and you are going to have a stronger hands. Patience and discipline are not things that can be built that easily, it takes hating everything you do for a very long time but grinding anyway, if you can grind while hating without interruption, you build that mindset to become very good.