I too was in the same boat up until March this year. Quit my S/W job and moved back to take up farming on a full-time basis.
My first and foremost advice for you before buying land is to ensure that you have local support (from outside as well as inside the family). Mr. Rajan Mathew/Savera farms and few others have posted their experience on buying land in TN/Karnataka. You may want to go thru the threads. BEWARE of brokers if you are interacting with them for the first time. I would prefer going thru someone who you or your close family members/friends know of. As well catch hold of a good lawyer who deals with agricultural property.
Once you identify the land and after verification of documents, you should consult someone who can guide you on identifying the ground water level in the farm and neighborhood, if there isn’t already any water source. There are also lots of water conserving techniques available in this forum as well as on the net.
Drip/Sprinkler usage can reduce use of water to a great extend. There are subsidies available from Center/State for the same.
Talking to local KVK helps. There are trainings that you can plan to attend. As well, plan to visit few farms. Talking to local farmers who use good agricultural practices is inspiring in itself.
In my opinion, agriculture, if done with little foresight and some smart planning can give you decent level of money. Again it is a “job” where you learn from your mistakes and improve upon. Pl. go thru some of the threads where members have visited well versed farmers.
Last but not the least, have sufficient funds to survive till you start seeing positive cash flow from the farm.