Swami,

Better to take instruction only from our family vAdhyAr swami as there are so many versions told/followed by different families.

As much as I know, deekshai is usually observed after the death of parents. It should be observed for a chosen period of 12 days (at least) or 1 mandalam or 1 year.

But observing deekshai is not that easy. I have heard through others that we will have to observe the following. 

1. No kshavaram/haircut for the chosen period
2. Should sleep only on the floor.
3. Strict brahmacharyam.
4. Nitya Sraadham
5. In addition to our usual food kramam, even food based on asafoetida, fenugreek, red chilly, milk also should be avoided. Green chilly to be used as a substitute for red chilly.
6. Food strictly only twice a day (most of us follow it already though so-called breakfast has entered our culture, especially for office/school-goers)

There might be more such restrictions or edits to my list and your question is best to be answered by vedic scholars and champions like Velukkudi Swami only.

-Adiyen