Optimizing your landing page

There is no need for me to prove to you that an optimization in your website's landing page will improve your Return on Investment (ROI) and your Rate of Return (ROR). As a matter of fact it is probably one of the hardest, most over-looked, and most important parts of SEO for a website. It is merely the showcase of your business, it is a fact that most of the visitors will simply decide whether to stay or not by simply looking at your home page.
Then, what should I be doing to prevent this? I've thought of this same question, and I've came up with the following statements, check right now how well you are doing the job:
(They are not in any particular order)

1. Your homepage is persuasive and it makes the visitors feel confortable:
   A common mistake is writing on the go the content you display and forgetting to check for errors, the text you write on your homepage is probably the most important one, and errors on it will make you lose all your credibility. Other usual errors are the lack of images, low resolution images, unconnected images... The visual aspect is even more important, since it determines the visitor's first impression.
2. You provide easy navigation that focuses on the most important links
   You must always show the visitor clearly what the next step should be. Brighter colors, out stand from the other links, do it however you want, but make sure that there is a path from the homepage to the result you want to achieve, whether it is to contact you, view your showcase, buy your product...
3. Your content resolves any possible doubt the visitor might have
   People won't know what your incredible product is, so for example an "About" page is a must-have. If you are unsure on how to organize the doubt-resolving content consider building a FAQ, which provides easy access to all possible problems a visitor will encounter
4. Your copy has been optimized to capture visitors
   The content you write is the most important part once a visitor has gone past the homepage, he has already decided that your site "looks" worth watching, now you must prove it with content. Test whenever possible what is best for your niche, long text? short text?
5. Your idea is clear after no more than 4 seconds of looking at your homepage
   If that was not true then you have to redo it. Your main point, idea, product, basically what you are offering must be completely clear for the visitor after no more than 4 seconds. Too much information without something in common and the visitor will probably be out, visitors want to know what they will find before having to actually search for it.
6. You think your homepage is great
   This is the most important one, Do you think your homepage is great? If you don't then don't waste your time reading this lists, delete it and start from scratch, do something you consider good, then you can bother with the tiny details.

Hope you could agree with all the statements!