Before you get started building your landing page, you will need a number of things to a) make your offer actually have a point; and b) facilitate the creation of your landing page.
One thing you absolutely must have before you get started is an auto responder. Without any auto responder, you are tossing potential bags of money in the garbage. Rather than creating a relationship with customers and potential customers – and giving yourself the opportunity to attempt future up-sales -- you're allowing them to leave and never return.
In addition to an auto responder, you will need to have an actual offer that people want to buy. You may want to develop a product, such as an E-Book or a piece of software.
If you don't have the skills to do either, you can always hire a professional to do it for you through Elance.com or Guru.com. You will then either want to sell this product and attempt to get subscribers from your thank you page – or you will want to get subscribers by offering the product for free (which is what many Internet marketers now do).
Another thing you absolutely must have before you get started is a check out service. You may want to consider Paypal, Click Bank, or 2 Check Out. All of these services will allow you to make transactions quickly.
Another thing you must have before you get started is a set of graphics, which usually includes a graphic header, a check out button, background wallpaper, and a half-decent picture of yourself. You can probably provide the picture of yourself, but you might want to hire a professional to do the rest.
Another thing you will need before you can get started on your landing page is some way in which to create a realistic signature. http://www.vletter.com is probably your best bet; but, if you're on a budget, you may want to opt for simply using a word processing program.