You need to find lots of different places to approach for funding, and have different types of funding. Don't be dependent on any one source of funds for your organization, or large projects you take on. If there are diverse funders for a project, no single funder can take control of it. Also, funders rarely like to pay all the costs related to a single project, they like to see that other places have been approached for funding as well. Internal fundraising such as events, memberships, user fees and donations are also a part of funding for your organization overall.
Organizational memory is important for grant writing.
The fundraising process is annual and ongoing. Establishing a relationship with funders and an awareness of when grants are due is important. Whenever you write a grant that's rejected, try to find out why. This will help you learn more about the art of grant writing. Some kind of grant writing policy that corresponds with your organization's goal plan should be introduced.