There are two general categories:
1) Important things for search engine optimization (SEO
2) Important things to convert clients
It's important that you have great, detailed content. For this it might be worth having a blog and regularly update your site with interesting and relevant information regarding your niche of carpet cleaning.
You pages should have multimedia content - written content, images and even videos if possible.
There is a fine line that has to be walked between writing content for search engines and for people.
As a general rule you want at least ~500 words per page, and you should sprinkle within the text they keywords you are trying to optimize the page for.
For converting clients:
Have a contact form on several places on your website on each page. Have a clear call to action to prompt people to fill in the form e.g. Fill in form for free quote.
Make sure your phone number is bold and visible in the top right hand side of all the pages, so people can easily find your phone number and call you.
These are some basic tips.
Any questions, post here.