Lets say you have just graduated from uni/college and you have a wonderful idea which you think you wanted to do. You know programming but you don't know the relevant skills to make it happen { Learn the relevant skills [lets say ios programming or ruby on rails for web app etc] }, neither you know what it will take to make it happen, time and resources.
So my question is
Should you go to industry to learn the skills you need for your personal start-up {danger is you may lost in job circle}
Or
Keep doing what you wanted to do {danger is, you may not know what is the right way to do it because you have no mentor}
Depends what you like the most:
Definitively you should learn the basic technical skills you need for your personal start-up. You shouldn't be afraid of getting a job to learn technologies in an applied way. Start doing a small product in your spare time. You will see when is the time to quit to concentrate only in your product.
Either avoid jobs that are too demanding "full-life", so you have some spare time for your projects. On the other hand join an startup so you can see how things are done and not but remember that is really demanding.
Besides that, if you really want to realize an idea and don't have the tech skills needed and you prefer getting right the market-fit, you should focus on creating and validating the business model and find a technical co-founder.
IMHO, if you love tech and programming, start doing something small while keeping a safe job, get skilled, get experienced. Try to find a mentor, someone who is in the same path as you but some years advanced, and is willing to share experiences with you.
More ideas: http://www.micropreneur.com/
I believe perhaps you are making some false assumptions, specifically:
1) You need a job to get a mentor - not true. You can start your own business and still have mentors. You had mentors in school didn't you? If you want a mentor, focus on finding a mentor, not a job. You can find both business and technical mentors.
2) You need a job to learn - while it is true that on the job training and practical experience are valuable, they are not the only way to learn. Where would we be if Bill Gates had decided to work for a big company first instead of leaving college to start Microsoft?
The questions I would suggest you focus on are:
1) Does your "wonderful idea" make business sense? Is there a good possibility that if you work on it that it could lead to the point that you could make money with it? This is your reality check.
2) How will you live while you work on your idea to the point where it will support you? If you can live at home and your parents are happy with that then great, I would say give yourself 6 months to 1 year and go for it. When you get to be 35 with a wife and 2 kids it is unlikely that you will be in a position to take a year off without pay. Do it now while you can. Assuming you work sincerely and diligently you will learn a lot and get invaluable experience in that 6 mos to 1 year. Of course if you party every night and hang out with your friends during the day it is another matter....
At the end of the year (or whatever amount of time you gave yourself) you should have a very good idea of how well you met your goals and if it looks like the business will be viable. By this suppose you estimate it will take 8 months to build your product and another 4 months to get enough customers to make it viable as a business. Now at the end of a year you found it really took 10 months to program and that you have just a few customers; well you would clearly see that it is worth sticking with the business for another 3 months to see how many more customers you will get. If on the other hand at the end of the first year you are only 20% done and someone else has just come out with a product like yours only better then you know it is time to go do something else. Even in this case you will have gained valuable experience.
JonnyBoats missed one of the false assumptions.
3 - You may not know the right way because you have no mentor.The odds are extremely high that whatever you start with (regardless of the person's background that is building it) you are eventually going to throw away a large percentage of it.
The ONLY right way, IMHO, is to build something and put it out there. Does it work? If yes then you did it right.
At some point your clients are going to tell you exactly which direction you need to go. At that point, and not until then, will you know what parts of it were right and what parts need tossed. A mentor can't help you with this.
Also, one thing you're eventually going to figure out is that 90% of the time the underlying technology is immaterial to the success of your project. However, 100% of the time the odds of success is going to depend wholly on your ability to execute.
In other words, don't throw new stuff in there because it's hip, cool or someone said it's the only way to go. Use what you know and expand on that.