Making photographs is only part of process. What to do with them afterwards is another issue that can often get overlooked.
Using programs to store your images is critical, instead of having them in various folders around your computer's hard drive.
One of the most popular programs is called Adobe Lightroom. This program is powerful and has tons of options for storing, organizing, and even some post processing.
The other program, which just about everyone knows about, whether you're a photographer or not, is Adobe Photoshop. This program is the workhorse and is limited to your imagination. It's so powerful at manipulating photos, and works perfectly with Lightroom.
Most DSLRs come with two slots for storing memory cards. My Nikon D810 has a CF card and an SD card slot. These two slots can be configured in a variety of ways. My method is to have both cards back up to each other, creating duplicates. This is in case of a card failure.
The card holders can be set up to expand storage capacity, in case your card is a relatively small volume. This will treat the backup card as an overflow in case you fill the first one entirely. It is a great option if you are taking a lot of photos for family and don't care too much if you have a card failure. (family photos can still be important!)
However, if you are a professional, shooting weddings, or some other client work, a memory card failure is not an option. You will lose business and learn the hard way of backing up important work.
A tip for those using a D810: I use a CF to SD card adapter which I bought off of Amazon. This allows me to only use SD cards, which my MacBook Pro has a dedicated slot for on the side. If I were using CF cards, I would have to purchase an additional adapter for those cards to be read. The adapter works flawlessly and makes my workflow that much easier.
There are limitless ways to organize your photos. It can be quite overwhelming watching YouTube videos and seeing how other photographers organize their pictures. The simplest way I have yet to see photos organized is by the year and then by month.
2018 > 01 January
Using the numerical system in front of the month allows them to be stored chronologically. If you type in the name instead of using the numbers before them, your folders will not be in proper order.
Having monthly folders is simple and effective. All of my photos get imported into the month I am shooting.
Year > Month
Previous Years (stored on another HDD)
As you can see above, my Lightroom Catalog is named "Lightroom Archive." This is the master folder and where LR will store all of the pertinent information regarding where the files are stored and what edits have been applied.
I keep the current year (2018) stored on my MacBook's internal SSD (Solid State Drive) and the remaining years stored on a external RAID drive, which is connected to my network, so essentially it is a network drive (NAS). The network drive is connected to my router, and the internet, and is accessible from anywhere I have an internet connection. The RAID part of the network drive refers to "redundant array of independent disks" and all that fancy lingo means is that there are two hard drives that function together to make mirrored copies of each other. This is extremely important as conventional hard drives are prone to failure. In the case of a RAID, if one of the drives fails, you still have your photos stored on the second drive. You can replace the failed drive and it will copy the information back to the new drive, giving you yet again two copies your photo library.
(I should note that RAID arrays can be 2-bay or 2 disk, all the way up to 12-bay containing 12 hard drives, and can be configured as RAID 0, 1, 5, 6, 10, etc - but this is getting carried away and you can research the different uses for your needs)
Using a conventional hard drive (one you plug in via USB or Thunderbolt) is another option if you don't want to set up port forwarding on your router and map the network drive to your computer. If you are backing up, it would be wise to use multiple external drives, to have multiple copies of your library. They even make RAID drives that are plug and play and are "direct connected" (via the USB or Thunderbolt - these are called DAS drives). These drives will not be on your network as they are plug in only, however it is a cheaper, faster and easier option than setting up a NAS drive. The trouble of setting up the NAS pays off because of its convenience, but it also comes at a higher cost.
Using one large external drive to back up your computer is a great start. If you don't have a massive photo library that doesn't take up a lot of disk space, you may store them all on your internal drive. You will want to make a complete back up of your internal drive using the external drive. TimeMachine is an easy way to make backups, but you need to be sure your external drive is larger than your internal, so you have room to grow. Lets say you have your photos on your computer's internal drive, and then you back up via TimeMachine (TM), another easy way to make a third back up would be to use a cloud service. Microsoft has something called "One Drive," Apple has its own iCloud storage. There are many cloud options at many different capacities and price points. These are usually an annual cost and are more expensive than using an external drive. However it is extra insurance against losing your photo library, especially since it is stored in the cloud and "offsite" in the event of a home/office disaster.
Another way to further organize and quickly find previously taken photos is to use "keywords." These help you remember where you were or what you were shooting. This is helpful if you do not remember which month you were traveling to Japan, or what year it was. Keywords are something I have not implemented into my photo organization method yet. Do as I say, not as I do! The keywords are applied when you go to import your photos (Lightroom users).