1. The land is in which city? Rural or Urban.
2. Constructed or not constructed.
3. History of the plot. (For example agricultural land, converted or non-converted etc?
Such information will help in giving you an accurate answer. But till you give that information, here is what I can say.
1. Get the record for last 35 years for the land. If you have dealt with land earlier, you will be able to read and understand legal papers (I can now understand land records and legal papers if they are in English).
2. Hire a local lawyer (should not be a agent/broker etc) and pay him money to check legal papers.
3. Check for the possession of the land. Go to the area where plot is located and ask around. Always get a Encumbrance certificate for the plot.
4. Do not pay any advance (biana, peshagi etc etc). Pay the initial amount after signing agreement, and keep the initial amount to around 5% of total amount.
5. Always have a fair exit clause for both parties on the initial agreement.
6. Pay the rest of the amount on registration day, take possession immediately.