To initiate the process of searching for grant giving organisations, you should explore the options on your search engine. It will show you a list of search results from where you will be able to contact the organisations and present your proposal.
Newspapers are an effective way of keeping yourself up to date, therefore, you should subscribe to famous newspapers and visit the relevant pages on a daily basis. This way you will not miss an opportunity and have the chance to achieve your goal.
Try reaching the chamber of commerce in your locality. These are non profit organisations and often prove to be a valuable source. They can provide you with plenty of contacts, which you can reach with your dream of getting more grants.
You can also take help from the regional association of grant makers. They usually cover more than 50 states and thus they can help you in attracting more grants.
The Catalog of Federal Domestic Assistance is an agency that has the contact details of all organisations that are currently giving grants.