I agree with several people as far as needing perseverance and belief in yourself. But I also think TOO much information -- otherwise known as "information overload" -- can prevent some from pushing ahead. I know it frustrated me to no end for a while. I just had to pick ONE method and focus on accomplishing it until I saw results. I think a lot of newcomers to internet marketing get taken in on all the different aspects of creating an online business and they get overwhelmed.
My tips for not succumbing to info overload:
1. Stop reading your emails. I get a ton of emails from different marketers trying to sell me stuff all day long. If you're serious about starting your business, you need to focus. Once you get set up, you can go back to checking your mail.
2. Focus on creating a squeeze page and building a list. I think that's the most important thing you can do. Some marketers will say you don't need a list to make money, and the truth is you don't. But you lose the opportunity to create ongoing income if you don't have those buyers on your list. And even if they don't buy, at least they're still on your list. You can keep offering them free stuff and promote your offers until they DO buy.
There's probably a bunch of different answers to this question, but that's my take on it. If you're new to internet marketing and are in need of free resources, check out the link below. Hope my comments help someone. :-)