In order to determine the success or failure of a web design, is not what the common belief seems to be which is visual. Success is determined by the ability to create usability. This in terms dictates that the user or potential client dictates every move based on if you utilized principles of good web design.
Is the ability to not enable a potential customer to think, therefore they need to be guided in exactly what you need them to do such as click this button here and win a prize, or move to the next section this way. Everything has to be self-explanatory from navigation to content to call to actions, third-person direction is key.
Users and potential customers are not patient, you have to make sure that the layout produces a quick smooth transaction that doesn’t delay. The less action it takes for a user or customer to use your site the quicker it is for them to build a sense of trust, so if you ask the user to subscribe if that movement of the site produced a quick relationship, they are prone to subscribe without hesitation.
Always focus the user’s attention with either bold typography or a picture that stands out by creating emotion. If you use this principle to attract and draw attention, you can guide a potential customer in the direction you are wanting.
These are just a few of the principles of good web design. To see all 10 principles check out Smashing Magazine and look at their article 10 Principles of Good Web Design.