Carnatic Violin strings are cross tuned

A string is tuned to the tonic of sruti (for instance, D#), and E is tuned to its fifth (A#)

G and D strings are tuned an octave lower to the same D# and A#

To begin with, the first 4 notes of the scale are played on the A string, and the following notes on E. (Tonic is always the open A string). As the strings are cross tuned, you can follow the same pattern on G and D strings (open G: Tonic)

Fingering for Ragam Shankarabaranam (comparable to the Major scale) would be the same as G major scale starting on G and D strings. (Open G, gap, note, gap, note, note etc---openD, gap, note, gap,gap, note).

For other ragams, we should find the corresponding notes and finger accordingly. 72 basic ragas: http://en.wikipedia.org/wiki/Melakarta

Usually finger 1 is used for Ri and Dha, 2 - Ga and Ni, 3 for Ma and Octave Sa from open positions. Of course, this changes when we move up to higher positions. Different fingering styles exist. Single or multiple finger oscillations and slides are used more often than plain direct note fingering, so fingering chart gets complex.

Akella Mallikarjuna Sharma's videos demonstrate good basic technique: