how to identify negative links to my page

So I did some bad linking to my page some month ago (hundreds of quick & cheap links from shady places)

1. How can I find out which of these links hurt my sites ranking

2. and how can I most effectively remove/unlink them?

Cheers

is hard to aswer, but the most common hint a link could be bad is if it comes from a domain that has been de-indexed by google.

About the remove part you can either contact the domain owner and ask to have the link removed.