For editing website templates all you would require is an html editor like Dream weaver, Photoshop, FrontPage or Go-live. Most of these html editors are (what you see and what you get) kind and have a user friendly interface. You can do two types of editing to your web-templates. One is content editing and the other is graphics editing.

Editing the content of your web templates
The template provider would have supplied you with file along with your template. This is the file that you would require for editing content of your templates. You can edit content using a text editor or an html editor software program.  

Editing Text Editer
Editing using text editors is the best possible way to edit your templates. This will ensure that your html coding remains clean and no unnecessary junk code is added. But of course you need to be some what conversant with Html to hand code your templates. Notepad is probably the most well-known of all text editors. Other than Notepad some other good and advanced text editors

Editing using Html editors
Making use of an html editor is probably the easiest way of editing templates and would be useful to those who are not conversant with html. Most html editors are user friendly and have an easy-to-use interface.

Handy tips for content editing 

1. Make sure to change the title of all pages. The title can be a keyword or words that are most repeated in your content. It can also be a description of your webpage. For instance you can use as the title for a webpage related to tourism in Florida.
2. Change alt text of images and keep the alter text as a keyword. Search engines read images but they do ready the Alt texts. For instance you can use the tag for a Florida beach image.
3. Make sure to add proper anchor text to all your links. Anchor texts are given special importance in search engines.
4. Give proper headings to all your pages. Heading can contain specific keywords. Headings are given using h1, h2, h3 tags. Text with-in heading tags are given more value by search bots. 
5. Be sure to check for spelling mistakes, grammatical errors, broken links and misspellings before loading the site
6. Provide contact information.