If you're starting from a new document, we've set up a short example showing how to use accents which you can use as a template:
Open the 'How to use French accents in LaTeX' example
If you're working from an existing document and having problems using accents, the first thing to try is to insert the following lines in the document preamble:
\usepackage[utf8]{inputenc} \usepackage[T1]{fontenc}
We include this in our default paper template, but if you've started a blank document or used a template from another source you may need to add this line in yourself.
With this package included, you should then be able to type characters with accents normally.
Finally, an alternative to typing accented characters directly is to use LaTeX's accent commands; see http://en.wikibooks.org/wiki/LaTeX/Special_Characters for more details.