The answer is pretty simple actually; unique content that is useful.
Most internet marketing guru's will not like that answer because they're always pushing some angle in regards to backlink building, onsite optimization or social media pushing.
It's all nonsense.
If you've been studying internet marketing for any period of time then the Adsense formula I use is so simple it will make you upset:
- Pick a keyword you want to write about (long tail or short tail, doesn't matter)
- Do an image search based on that keyword. Choose 4 or 5 images and crop them to around 500px600px (give or take a couple hundred pixels) name the image file after the keyword (i.e 'green_lounge_char_1.jpg, 'blue_lounge_chair_2013.png'')
- Write your content. Start by writing a paragraph and use the keyword in it. After the first paragraph place a picture. Write another paragraph. Add a picture. You get the idea.
What do you write about?
To me, adding content is the most difficult part. Why? Because I have to come up with enough quality information for a 600 word article. Some people write less, some a lot more, but I try to keep the page small and to the point.
I like to write in the 1st person perspective. I like to tell a story, or an ancidote that revolves around my keyword in some way. This makes the content flow more naturally then if I were just writing 'FACT! FACT! FACT!'. Make your writing personal and unique. Your reader will thank you and Google will reward you for it. I'll show you a sample paragraph in a later post.