Giving up means failing.  If you continue to get the content out there and plenty of it, you will see some returns.  I have to say that articles  I posted over a year ago are now starting to get traffic and make me some money.  Not a lot, but some.  When you have doubts, you paralyze yourself and nothing gets done.

 As an aside, Hubpages are a great place to post things.  Even if it is a over saturated niche, you may not make "sales", but you will get some Adsense profit.  I continuously make money from Adsense with my hub pages, even though I don't get many sales.  Of course, the more hub pages you publish, the more chance you have of making money with adsense.  If you are stuck and cannot seem to make money, go to Hubpages.  They are free, they take anything for content, really (no restrictions or crack down like Squidoo).  Try it, challenge yourself to publish a Hub per day.  Definitely use the adsense to your advantage.  On a more popular niche, you might get a click or two per day at around $0.50 per click.  Now multiply that by a hundred pages.  Can you say passive income?   There is no maintenance required, you just set it and forget it.  That's what I love about Hub pages.