A siva mantra seems to be offering quick results when it is recited properly. The mantra is called as "OMSIVASIVAOM".
It seems to reduce our karma and the proper ways of reciting it described as follows.
- The person who recites this mantra should be 21 years old.
- The person reciting the mantra should avoid Non veg food.
- A new yellow colour cloth should be used to sit for reciting it.
- One should start reciting it on no moon or amavasai day is a better day for starting it.
- Reciting it in temples of Lord siva will be very beneficial.
Om is the moola mantra for siddhar thirumoolar. Omsivasivaom consists of shakthi mantra. om is a single letter mantra appear 2 times and siva mantra siva appear 2 times and this is the mantra that have sivashakthi equally. omsivasivaom is the mantra for devotees having a family.
Expanation for origin of omsivasivaom mantra in tamil - http://www.aanmigakkadal.com/2013/04/blog-post_5.html