Sometimes though the decision you made at the outset can be wrong. No amount of persistence or creative marketing will yield any sizeable success if you're trying to sell ice to Eskimos. Sell them snow mobiles though and you have a much better footing on which to build further successes. If you want to get to another country as quickly as possible, it's better to step into a plane than to board a cruise ship and persuade the captain to increase ship speed. The initial choice is key.
"Sometimes you have to give up the fight and walk away, and move on to something that's more productive." Donald Trump isn't a likeable person but his words ring true. You owe it to every idea you start to devote all your smarts and effort to it, but if it continues to bear no fruit then you have to think carefully and decide what's best moving forward: persist or abandon ship and start afresh? It may hurt to acknowledge a failure, but your decision must be guided by what's best for the future, not on what has already passed.
Trump adds: "I've learned that there's a big difference between perseverance and stubbornness. Stubbornness involves me forcing things to work, while perseverance requires me to work consistently with what's already working."
Motivational catchphrases like be positive and never give up need to be taken with a pinch of salt. They are emotional without much acknowledgement of the actual conditions, and can inadvertently encourage you to punish yourself as you persist at low yield endeavors.
Making a wrong decision is not the end of the world, but it can be if you refuse to correct it. The hole you're in will continue to deepen. Just as you must be willing to work hard, so too must you be willing to radically adjust course where necessary. Heart and head need equal input.