Lord Vinayaga is the remover of obstacles and almost in most of the countries in the world worship lord vinayaga in a different name.Worshipping twin vinayagar whicha are called as "rettai vinayagar" is very beneficial for various purposes.Stars like thiruvathirai, thiruvonam, visagam are suitable and most beneficial for worshipping lord vinayaga. Theipirai sathurthi ,Panchami tithi are also suitable for worshipping him.
For sevvai dosham:
worship lord vinayaga during theipirai sathurthi by offering arugampul malai
For chandra dosha:
worship lord vinayaga by offering kolukattai using garr rice.
For bonding between husband and wife:
worship twin vinayagar by offering mangos and give it to couple who are poor.
For removing diseases:
worship twin vinayagar on thiruvathirai star by offering a vila garland
For removing poverty:
worship twin vinayagar by offering panchamirtha abhisegam during panchami tithi.
For good events like marriage:
worship twin vinayagar by offering a cloth which is designed with flowers
For naga dosha:
worship twin vinayagar during tuesdays by lighting ghee lamps
For unmarried girls:
worship twin vinayagar by doing santhana abhisegam for getting married soon.
For eye problems:
worship specially nethira vinayagar, specifically in swami malai for getting cured from eye problems.
Thanks to jaghamani's blog.