Anytime you have to convince someone to accommodate your request, it helps to consider things from their perspective, and to demonstrate that you have done so. Find what they are looking for and keep it front and center when you write your appeal.
For instance, if you are looking for a job, start with the job ad and the description of the position in it; look it up on the company website, too. Look at the key words they use. What are they looking for? Choose the ones that best describe you and use them in your cover letter. (If none fit you, look at a different job.) Try to demonstrate that you meet the criteria without labeling yourself with their keywords; the caveat is that if you think the cover letter may be thinned by computers, use the words exactly. So if they want a team player, describe how you work well in teams, or list team efforts in your resume. They have told you want they want, so show them that you have it. Don’t assume that a reviewer will connect the dots for you; they are looking at a lot of job applications and may not see what is so obvious to you.
Similarly, if you are applying for a grant, look at the goals of the program or the grant. What are they looking for? Find the key words and use them liberally in your application. For instance, if they are looking to help underserved communities become more educated about food, give them the data to demonstrate that the community is underserved, then discuss how you will help the community learn about food and nutrition. Especially if it is a stretch, if you are looking for money to fund something related but not obvious, spell out exactly how you fit with their goals. Don’t assume that a reviewer will connect the dots for you; they are looking at a lot of grant applications and may not see what is so obvious to you.
The idea is to make it easy for an employer or granting agency or whoever you need something from to see why helping you will help them achieve their goals. Spell it out clearly, even if it seems painfully obvious to you. Take time to connect the dots so that they see the picture you are presenting, and you increase your chances of achieving your goal.