You can solve sample papers made by different prominent coaching hubs across the country. These are available on internet.
Apart from all these, you can solve previous year questions. These are also available with their answers.Previous year questions is highly recommended to every candidates to check their preparation level.
Sample papers is available on: ” http://www.medicine.careers360.com/articles/neet-sample-paper” .
Previous year questions are also available on its official sites.
All the best of your exam.