It is also commonly known as a Squeeze Page. These web pages are very targeted and focus on capturing information about a visitor.
Below shows the screen captured for some of the squeeze pages.

So what are the content that are needed to be in a squeeze or landing page?

It should cover the followings:

1) A sub-heading leading your prospect into the page.
2) A short sales message containing 5 to 10 benefits of the product you are
promoting.
3) A submission form where he or she can enter their details.
4) A call for action messages

After your visitor submit their names and email addresses, they should be taken to a sales page. The sale page should cover the following convincing messages:

1) Why there is a need for your product in the market?
2) Why your visitors want to buy from you and not from your competitor?
3) What benefit can your visitors get if he buys the product from you?
4) Why there is a need to buy the product now and not other time?

I admit that I am not a good writer and have a poor command of English. I may not be able to write a good sale letter. What I did was to engage professional to bid on my project and help me create a convincing squeeze and landing pages.

Alternatively, if you have tight budget, you could model popular internet marketing expert such as Ewen Chias to see how they write a good sale letter.

Think about it and find the above information right!

Cheers!
Patrick