HOW TO INVOKE THE RAIN GOD?

As per Vedic tradition, there is a Yajña known as the KArIri Ishti for invoking the Rain God.

In addition we have:
1. VaruNa Mantra
2. RishyaSringa Slokas
3. Azhi Mazhai KaNNa ( of TiruppAvai)

These are very powerful in invoking the rains.
In Music , it is Amrutavarshini RAga.

CANONS OF PHILANTHROPY -- DANAM

As per TaittirIya Upanishad i-11, the canons of Philanthropy ( DAnam) are as follows:

1.Give with faith ( SraddhaYA deyam)
2.Do not give without faith. (aSraddhayA adeyam)
3.Give in plenty (SriyA deyam)
4.Give with modesty (hriyA deyam)
5.Give with sympathy ( bhiyA deyam)
6.Give with knowledge (samvidA deyam).

Whether Surgery is mentioned in the Vedas?

There is reference in the Vedas about Surgery and Dentistry.

Surgery
The Asvins fixed an equine head on Dadhyac. -- Brihadaranyaka Upanishad ii-5-17

Dentistry
Dentistry is mentioned in the Vedas. -- Aitareya Brahmana iii-6-3, Aitareya Brahmana ii-1-5

What are the Sutras of Shukla Yajur Veda?

SUtras pertaining to Sukla Yajur Veda:

1.PAraskara Grihya SUtra
2.KAtyAyana Srauta SUtra
3. KAtyAyana Sulba SUtra