Best First Step: Ask for Removal on the Site Itself
Now that you've identified your bad links, you can now start the process of getting rid of them.
Here is are some links for a site downloaded from Google Web Master Tools. I've put them in a spreadsheet and started to analyse them.
The best way to start link removal is to go to the site itself to request link removal. Sometimes there is a contact form to request removal and, on the other end, in the best of cases, a person who after receiving the request, will immediately remove it for you. This is what happens with reputable site.
How to Find Bad Links
How to Remove Bad Links Part One - Ask for Removal on the Site Itself
How to Remove Bad Links Part Two - Use Whois to Find the Owner
How to Remove Bad Links Part Three - Create the Disavow Tool Text