You can submit your sequence/molecular data to NCBI ahead of time and choose to keep them private until you publish your paper.  It is preferable that you submit your data early to ensure that you have your records processed and available on time. During the submission process, most of the submission tools will present you with a menu to choose (1) to have your data released immediately or (2) to have your data released at a specific date. Otherwise, communicate your preferences to the database staff.

Individual databases provide specific information on setting and changing data release dates:

• GenBank: See the Confidentiality section on the GenBank home page.
• SRA: How do I change the release date of my SRA submission?
• BioProject and BioSample: BioProject FAQs and BioSample FAQs each include FAQs concerning record release date.
• dbSNP: What are dbSNP's "Hold Until Published" Policies?
• GEO: Can I keep my data private while my manuscript is being prepared or under review?