Successful website means how many unique visits does it have in a given time frame.Traffic depends upon several factors and i am going to talk some of the principal factors which are really really important in order to have organic traffic towards the site.You dont have to be SEO expert , so this basically means you even if you dont know what SEO is , you still can rank in Search Engines. Just follow the basic rules.
RULE 1: Unique Quality Content.
Search Engines love Quality Content mind you .It doesnt matter what type of niche you are having or much the competetion is there for that particular niche. While creating the contents, you should have in depth knowledge about your niche. Instead of outsourcing your work to somebody else, just feel the passion within yourself and you are going to write something outstanding. If you have outsourced your work to somebody else, make sure that the work is original. You can take the help with antiplagiarism software.
RULE 2. Keyword Rich Content.
While writing articles you should always keep in mind your niche. Make sure that keyword gravity in your article is appropriate.Do not abuse the article by excessive use of keywords throughout your article. It is a best practice to use keyword atleast once in the first and last sentence of the article.
RULE 3. Use Images in your articles with appropriate Alt Tag.
Make sure that you use suitable images in your articles. Scale the image size as per the page layout.Also it is very important to give image's alt tag a name. Generally the image name is your keyword or very close LSI keyword.
RULE 4. Frequence of your posts.
Try to post atleast on article to your website per day. if you can post more its good but make sure it is unique.if you have huge stock of articles ready with you, good practice is to schedule your posts.Give 48 hours pause between the two posts.
RULE 5. Back Linking
Find the blogs and forums and boards which are related to your niche. Be an active participant there.Comment wherever you can but dont spam the boards.Leave a link to your website there.It will help increasing the pagerank of your website.
RULE 6. Take a Feedback.
It is very important to hear the people whom you are writing content for. Sometimes they can give you a fair idea about your content , how it is written.