The very best time to write your sales letter is while you are writing your eBook or other information product. During this time of creating a product to sell on the internet you are more aware of the benefits it will have to the final user. As you are writing or recording your eBook or other information product, write down the features and benefits of what you have to offer.
You can also use the details of your product to write powerful headlines. You will be emotionally connected to your writing during this creation stage, and that is when the best sales material will come through. You can share stories about how you came to write you eBook and tell your readers more about how this information will help them to achieve similar results and outcomes.
Go back and forth between your eBook and your sales page. Include the reader in the entire process and your sales copy will speak directly to them. Use bullet points to point out features and benefits that may otherwise be overlooked. Years from now you will be glad you took the time to write the sales copy early on in the product creation process.