For everything there is to do, the easy way to fail is simply not to try. In this I humbly disagree with Master Yoda, who famously noted:
Try not. Do, or do not. There is no try.
There is definitely a try, even if it doesn't lead to a do. And this separates winners from losers more surely than anything else. Trying does not, in and of itself, lead to success, of course. Depending on the goal, there are many ways to fail. But not trying surely leads to failure.
I was thinking about John Stockton, the recently retired Utah Jazz basketball player who typified "trying". He had a lot of talent, of course, so his trying led to success, but he will always be noted for his effort rather than his talent. In thinking about John and giving full effort, I wondered "why doesn't everyone always try"?
There is effort involved in trying; an investment of resources, if you will, and so one could argue that not trying when you know you will fail is prudent. But I don't think that's it. Not trying is not a calculated decision, it is emotional. People just don't like to fail. If you don't try, you can always reassure yourself with the false comfort that you would have succeeded, if only you had tried. Once you try and fail, that's it. Actually there is a gradient all the way from not trying to giving 100% effort. Sometimes people do something in a half-hearted way, and possibly this is their form of "not trying"; they can feel they would have succeeded if they had given full effort, and thereby feel less bad about themselves for having failed.
As I've noted before, I believe happiness comes from liking yourself. Things which make you feel better about yourself are "fun", and things which make you feel worse about yourself are not. Trying to do something you are not good at may not be fun, in the sense that you will feel worse about yourself for your lack of skill or success. This accounts for the wide range of things people do to have "fun"; different people are skilled at different things. Certainly you don't have to feel worse about yourself for not trying or doing all of these things. That is the "out"; if you don't try, you won't fail.
But... That's fine for discretionary recreational activities. But what about life itself? What about your family? Your profession? Your contribution to the world? In these things not trying is the surest way to fail. You may be able to convince yourself that your lack of success is due to lack of effort, not lack of skill, but that is secondary; your lack of success will be a fact either way.
The key seems to be to regard trying itself as a success. Yoda himself understood this, for he said:
Learn to lose as well as win, a Jedi must.
If you can feel good about yourself for your effort - regardless of the results - then you can always succeed.