If you are just starting photography, you might wonder "How and where do I store my photos?". The best answer is "Wherever you can easily find them.". However, you do NOT want them all over the hard drive or memory stick.
Some people store their images by the date they were taken. I do not file by date because I'd never remember on what date I went someplace, like to Cypress Gardens. When I search for a picture it is by subject, like Disney World, or Aunt Beverly. Also, the image files have the date they were created in them. Many people use a cataloger for keeping track of their photos. I don't, I just use a directory (folder) structure in Windows Explorer. I imagine that there is an Apple equivalent. If you do elect to use a cataloger (it's just a database of your images), you should still have your images saved in some kind of orderly logical fashion, a method that works for you. You do have to tell the catalog program, whether it's part of your editor or separate, where to find your images.
Some people store their images by camera if they have more than one camera. Something like "Photos\Camera\Year\Month\Location". So if they went to the same place twelve times over the years and used different cameras, they would have images of the same place in twelve different places on the drive. I personally prefer all of the images of one shooting location in one folder on the drive. The date and camera information is available in Windows Explorer and sortable.
The best thing to do is to figure out where and how you will store your images BEFORE you get too many of them, just in case you figure out a different or better method. No matter what method you come up with, each method may have an anomaly or two. Such as do I make a copy of the image to store in another category. NO, do not make copies stored in multiple places! You'll wind up with one that has been edited, and one that has not. That could lead to a disaster or confusion later. Use keywords, whether in the file in Windows Explorer (My OS is Windows.) or keywords in a cataloger.
I always keep the original image. That way I can go back to it and make other changes. If I make changes to an image, and I want to give it a different treatment later, I'll have the original image to start with instead of only a previously altered image. Not saving the original image could be a problem if you crop a 8x12 image to 8x10. Keeping the original saves the 2" that were cropped out. Storage is cheap. If I crop an image, I'll save the cropped version as another file. The original might be IMG_1234.JPG, I'll save the cropped image as IMG_1234c8x10.JPG. If I modify an image (lighten/darken; saturation; highlights/shadows, etc.) I will save it as IMG_1234adj.JPG. An adjusted AND cropped image would be IMG_1234adj8x10.JPG. Since I shoot RAW, I'll edit the RAW and save it as a JPEG with the nomenclature I stated.
If you will be saving RAW +JPEG, you'll need to decide if you want to keep the RAW and JPEG files in the same folder or separate folders. Some people save the RAW files in one folder and the JPEG in another. I tried this for a bit and found it was a pain to work with. I would view the JPEGs in Windows Explorer and decide which file I want to edit the RAW file. (Using the RAW editor is my first choice because it provides more control over the image characteristics.) I would find the JPEG and then have to switch to the folder where the RAW file was located. In addition to requiring duplicate folders, one for the RAW and one for the JPEG, I found switching file locations cumbserome. I decided that keeping the RAW in the same folder as the JPEG was much simpler to work with as the RAW file was right next to the JPEG file in Windows Explorer.
I store my images by subject, primary subject. Since I use Windows to view my images, I created a directory (folder) in the root called PHOTOS. That way I don't have to keep drilling down through to My Documents or My images. When I backup the photos, I simply backup the PHOTOS directory and all the subdirectories in it. If I were to use a cataloger, I would just tell the cataloger to use C:\PHOTOS. The cataloger will find all the images in each sub-directory. Everything is in ONE primary place. Below is a portion of how I store my images. Remember - What works for me may not work for you.
I only use date folders (YYYY-MM) if there are more than one date for images from a place as the date taken is in the file metadata. The metadata also contains fields for image title, subject, tags, and comments. The tag, subject, title, and comments fields are searchable with Windows Explorer.
The best thing to do is figure out how you want to store your images and what you want to use to keep track of them. Find a method that will work for you. Once you have a methodology set up, and follow it, you'll be able to find what you want easily, whether you use a cataloger or Windows Explorer.
Now, backing up your images - You do NOT want to have your images stored in only ONE place! If your hard drive crashes or the computer breaks or gets stolen, you could loose everything! You should at least periodically backup and whenever you add a bunch of images to your hard drive. External portable USB drives are inexpensive. I currently use a couple of Western Digital My Passport Ultras. Since I also back-up documents, spreadsheets, and any other important files, I try to do a backup monthly. I also use Carbonite on my primary computer. Carbonite usually backs up new files within minutes of being modified or added to the drive. Carbonite is my disaster recovery backup. If, for any reason, I lose my original and backups in the house, Carbonite has them in the cloud. Ideally you want one of the backups stored off-site. Many people keep a copy (on an external drive) at a friend or relative's house, or in a safe deposit box at the bank.
Do you want to backup on SD cards, thumb drives, or Solid State Drives (SSD)? That's fine. They are convenient and small. But be aware that these devices are electronic charge coupled devices (CCD). That means they store the information as electric charges in the memory cells. The cell charges will eventually bleed off, altering the data. Some manufacturers say years. But to be on the safe side, one should plug the device into a computer periodically and read them (look at the directory contents) to ensure that the cell charges are maintained. How often? Good question! Once a year?? Once every six months?? Who knows. But I certainly would NOT store important information on one of these devices and let it sit in a drawer for years. When the cell charges are depleted sufficiently, the data will become corrupt. I'd rather trust a hard drive if I was planning on archiving a device for for years.
As the technology changes, also change your backup strategy and/or method. I'll bet that there may be some people who have stuff backed up on 3-1/2 inch floppies. When is the last time you saw one of those used?
Have fun deciding on both your storage method and your backup method. Once you do, STICK TO IT and do backups regularly!