When you plan to make or restructure your website need to have into account some design considerations. First, the visitor need to be confortable when visiting your site, and a good visual apealling website will get that impression on your website. Links, graphic and images position, text alignment, and a site that comply with disability norms, are aspects to be considered in the field of usability. Second, upon designing a web site you need to follow the law of eye mechanics or movement of the eyes, and apply that concept to your usability guides. As these aspects mentioned before, ther are manny to take into account. I am sending the following link that will help you to clear any doubts about this interesting web design field.
http://www.usabilityfirst.com/websites/index.txl
Looking at the site you submitted I see that there is too much information on it.
First thing, never ever annoy your audience or visitors with pop screens from the beginning. In this case, there is an annoying pop screen that forces the visitors to choose from different selections.
Second, the page should be center, giving some extra space to the left margin at the Booking Details section. Third, check if the banner posted to the right side comply with the guidelines issued by the IAB (Interactive Advetising Bureau).
Distribute accordingly your content along the page, to make better organized. Like for instance, the Live Help! chat image on the left site plays an important role for the company because is the opening door to its Customer Service Hot Line. Therefore this image should be allocated to a better location like the right top side where the visitors can see it clearly in case they need help.
I see that there are manny more details to be checked, please keep positn should you need further assistance with this topic. Thanks.