How do I organize and store wedding photos after delivery

Use the folder structure your photographer provides
Most photographers organize images by event: getting ready, ceremony, reception, etc. Keep that structure. Add your own backup system on top of it rather than reorganizing everything. Consistent naming and sorting makes it easier to find images years later.
Store files in at least two physical locations
One copy on your computer or external hard drive isn't enough. Invest in a second external drive and keep it at a different location: a safe deposit box, a parent's house, or a trusted friend's home. If your house has a fire or flood, one backup survives. Hard drives fail unexpectedly, so redundancy matters.
Consider cloud backup for important selections
Cloud services add a third layer of protection. Upload your favorite 50-100 images or all final deliverables to a cloud storage service. This costs little and protects against total device failure. Don't rely on cloud storage alone because account access can be lost, but it's valuable as an additional safeguard.