Can you become a great writer simply by sitting in a room and writing?
How do you write about a man freezing to death if you have lived your whole life in the tropics, where the lowest temperature is 18 degrees Celsius? You can guess and you can assume and even research. But the best way to show a man freezing to death is actually knowing how it feels – or at least a part of it. Take a holiday in the Alps. You don’t have to actually get yourself frostbite*, but you have to know what it feels like when the temperature is below freezing point.
There are some things in life that most people will never experience. Taking someone else’s life, for example. Anyone who has gone down this road will know that it is no simple matter. If you’re writing a war story, should you go and join the army?** I’m pretty sure that’s not necessary. If you’re writing a serial killer, do you go murder people? No.
Even though you can’t expect to experience everything your character will experience, there is always a middle ground. Tiny everyday experiences can be elevated to fantastical fictional experiences. If you were robbed on the street by a man with a knife, you can relate to a soldier being held at sword-point for treason. If you stand outside while it’s snowing and you shiver through your thin jacket, you can relate to someone freezing to death.
Combine your experiences with knowledge and you might have a better chance at getting your fiction to sound and feel realistic.
Get out of the house and experience life. The more experiences you have to draw from, the better your fiction will be.
If you get a chance to travel to the streets of Israel where your WIP is set in, it can only do your story good if you go and experience that which your characters will experience.
* Though doing that will give you a better perspective.
** This too.
Disclaimer: I am not saying that you should go out and get yourself robbed just to relate to your characters better.