If you use WordPress to design your website then you should make sure to take advantage of the many plugins that are available to enhance your site. WordPress comes with a number of basic themes pre-installed. You can opt to amend these themes, build your own from scratch or buy a prebuilt theme. Once you have your theme you can then add other plugins to the site to give you more features. Some themes will require certain plugins in order for them to work. Some of the plugins are free and others you will need to buy so be sure to check this when costing up the website.
ContactForm 7 is a great simply to use plugin. It allows you to add multiple contact forms or enquiry forms to your site and they can be easily customisable. You can also set up auto responders and change the structure of the email that you receive once the form is filled in.
Another great plugin is SEO Yoast or All in One SEO. Both of these allow you to quickly and easily set up the SEO information needed on each page and allow you to edit what the search engine sees.