1. Make sure your budget is flawless. Have others look it over. If there is any question about what a line item is about, make it clear. Make sure you don't have any "miscellaneous" expenses, and if you do make sure that is the smallest amount. Also, in real life it never works out this way, but make sure your total income and your total expenses are an equal amount. It should go without saying that you'll have income in your budget. The grant giver wants to see where else you're securing funds. Include the grant you're applying for in your income. Put a realistic dollar amount on "in-kind" donations. All that said, don't make your budget obnoxiously detailed. "Office supplies" will do as a line item, you don't have to get into number of pencils and and paper clips.
2. Explain how you're project or program will be sustainable. Once the grant money is gone, how are you going to keep your program going?
3. Why does the community need this project/program? What have your successes been, in numbers? How many volunteers do you have? If you are just getting started, what are you projecting will get done in your first year? (How many people are you going to feed, how many visitors will you have to your clinic, etc.)
4. Don't include more than ONE point of contact, ONE phone number and ONE email address to contact you.
5. FOLLOW THE INSTRUCTIONS. The instructions trump any advice here. What the grant giver is looking for is in the instructions/directions. You want to show him/her what he/she wants to see.
Add your tips in the comments.