My understanding is that, you are interested in interstate migration in India. That suggests a focus on internal migration. A way to start is to collate, if not already done, recorded statistics by the national agency for statistics. Alternatively you could run a survey focusing on these internal migrants and here, a key question could relate to the place (city/town/village) or state of birth. Issues of ethnic origin could also be used a proxy for hometown and from this t=you get idea of where they migrated from.
Dear Sameer, a good way to capturer infomation on internal migration would be to use either census data (limited information due to few questions addressed) or your own survey (this allows a more detailled analysis as you may be more focussed on what you really want to analyse).
If you are interested in how the migration works und why people migrate, some qualitative, mobile methods might be helpful. The following article presents different useful methods: Monika Büscher and John Urry (2009): Mobile Methods and the Empirical. In: European Journal of Social Theory 12(1): 99–116.
To give some examples: You could participate in the patterns of movements, you could use time-space diaries or you could use digitally enhanced methods.