HOw can I design one good EMI filter?

Please help to design one EMI filter to reduce common-mode and differential mode noise.
How can I do design it? and what algorithm can I use in this work?

Thanks,

A well designed EMI-filter is found in the link below. It gives good differential and common mode suppression. Analysis can be done using any SPICE program.

http://www.lambdapower.com/ftp/Specs/maw.pdf