In addition to a general Internet search, Hindi grammar worksheets are available from the Central Board of Secondary Education (CBSE). The CBSE provides oversight for educational programs across the Indian diaspora.
The CBSE offers study and educational guides for multiple classes or grades on its website. A search through the CBSE Publications link on the website provides a variety of texts, examinations and other materials.
Other websites offer Hindi grammar worksheets and materials that are based on CBSE standards. A general Internet search will yield many English sites, but a more detailed search will offer websites such as MyCBSEGuide and UpToSchoolWorksheets which offer links to grammar worksheets in both English and Hindi for practice purposes. The Pearson Edurite site offers a DVD with CBSE-approved content.