1- When Should You File a Reconsideration Request?
A reconsideration request should be filed only after you have received a manual penalty notification in the Webmasters tools. You can file a reconsideration request from the Google Webmasters console. You must file a request only after you clean up your site or backlink profile which were going against Google Webmasters guidelines.
The request should not be filed in case of an algorithmic update.
Here is more help – How to write a reconsideration request?
2- How to Check the Quality of Backlinks Pointing to Your Site?
You may check all the backlinks pointing to your website using the Google Webmaster tools. After logging in, move to Traffic -> Links to your site and you will see all the links that Google has discovered until now. You can get an idea of the sort of links being generated for your website. Make sure there are no unnatural links pointing to your website.
More help-
How to build natural backlinks?
Link Farms
Link Churning
Penguin 2.0 Recovery Guide
Paid Links are a Violation of Google Guidelines
3- How to Clean up Your Link Profile?
Cleaning up your link profile requires time and patience. A proper analysis of site backlinks is required followed by link removal by sending requests to webmasters and using the disavow tool as the last resort.
More help-
Low Quality Link Profile Asking for Sure Trouble?
How to Use Google Disavow Tool?
What Exactly is a High Quality Backlink?
4- What is the Time Taken to Process Reconsideration Requests?
There is no specific time given by Google in this regard. However, most of the requests are processed in a few days. More help can be found here:- Google Webmasters Forum and Google Help Articles.
Also See:-
Google Working on Providing Samples of Unnatural Backlinks
How to Create Backlinks that Google Loves
Seo Secrets
How to rank in Google
Are You Making Your Website Vulnerable To Future Google Updates
Battle of Ranking Continues
