Research potential funders thoroughly. A quick look through a foundation guide isn't good enough. Then apply what you've learned. Don't ignore a funder's guidelines in the hopes of fitting your proposal into their niche. Don't overlook marketing.
Management is vital.
You must be able to demonstrate that your organization has the management skills and experience that can deliver success. Know your funder. Don't ask for hidden agendas but do find out about general trends or new ideas in which the funder is currently interested. Always work with a timetable. Make sure you have enough time to complete your application, so it is technically qualified, highly competitive, and timely.