Make sure to scope of the project you propose is achievable within the 8-10 months allowed by the grant. If your proposal is for work that is part of a larger project, you can acknowledge that in your proposal, but keep the primary focus on what you are asking Fulbright to fund.
Make sure your methodology is clearly articulated, appropriate for the project, and would pass muster if evaluated by a specialist in your field.
If using archival resources, identify where they are and confirm your access to them.
If you intend to work with a particular scholar, lab, artist, or research group, this should be clear in your proposal and there should be an accompanying letter of support/affiliation verifying the connection.
Fulbright tends not to fund proposals that appear to involve the grantee working for an organization on an ongoing project if it isn’t clear they are making a unique contribution to it. If you are proposing to work with an NGO, laboratory, or other established work group, you need to be able to articulate what part of the project is uniquely yours.