Managing your photos--a lot easier than you think.
What a surprising number of people don't realize is that every device these days pops up as a drive on your system, and that you can drag and drop your files onto your computer--even your phone. (And to those of you saying "everybody knows that already!" trust me; they don't.)
Commit to downloading
First, you have to make the decision--and stick to it--that you'll download (or upload) all your photos and videos within a day or so of taking them. It's a good idea to get in the habit of at least copying your photos and videos off your device and it really takes no time; once you've got a system in place, you can do it while watching TV, eating dinner, or playing with the cat. Why bother? The last thing you want to do is run out of space on your card at a key moment or lose your media if you misplace or break your device. If you want to keep it portable to share, that's fine. But you also want to be able to hit "delete" or "format" if necessary. And you need to commit to the plan. If you don't, you'll end up more confused, having to remember whether you downloaded something or not before you can start looking for it.
Figure out your need to retrieve
Don't just dump everything in your system's default folders (such as My Pictures), though they're fine to use as a root and might be easier to migrate if/when you switch machines. Figure out how you'll need to find them again, and how often. How do you remember? What's the first thing that comes to mind for you--where you shot something or when you shot it? Do you need different systems for different computers? While keywording and tagging are certainly best practices, they do add extra overhead to a process that you might not be able to maintain and you don't necessarily need to do it. And if you think you'll only need to find a given photo every now and then, you don't need to get very elaborate.
For example, I (obviously) use the photos I shoot for work differently than than those I shoot on my own time--and because the two overlap, I end up with a lot in both locations, but I keep them organized differently. At work I put everything in folders by camera name; at home, by date and location of the shoot. For a coarse level of retrievability, if you just use a utility to rename all the files to something basic but meaningful, like "stair cats in Queens," (plus a file number increment, of course) you can search the file system. Then it's pretty easy to visually scan the thumbnails for the photo you want. If you'll need to find photos more frequently, then it pays to step up to a program that, say, lets you flag the photos you like; flagging quickly narrows down the results of your search when you're looking, but doesn't take a lot of time up front (especially if you use software that lets you quickly scan and flag).
Get a card reader if necessary
For cameras and camcorders, it really pays to buy a card reader if you don't have the necessary media slot in your system, though most recent computers have at least an SD card slot. While you can connect the devices directly to your computer, standalone drives or slots tend to be a bit faster, and the goal of this exercise is to make downloading as painless as possible so that you'll actually do it regularly. Phones, on the other hand, tend to have inconveniently located spots for their flash media, and use tiny, easy-to-lose microSD cards. You're better off leaving those in the device. Tablets fall somewhere between, some with only built-in memory, some with easily accessible SD slots.
As a corollary to this, I also suggest you get a second card for your camera or camcorder if you don't have one already. They're pretty cheap, and, frankly, once you start downloading regularly you're bound to forget that you left the card in the reader regularly as well. Always keep at least one extra card in your camera or bag.
Choosing the right software for importing and managing your files is several stories on its own. There are tons of choices--free, cheap, or expensive, with variations in how many features they offer from the ultrabasic to the nuclear option. Though basic downloading and drag and drop are available within the operating system, a utility that lets you batch rename is a helpful complement (I use FastStone Photo Resizer for batch renaming). If you use some sort of cloud-based syncing, such as iCloud Photo Stream or the Eye-Fi system, to automatically distribute your photos from the device to a home hard drive or an online sharing service, definitely make it a habit to rename and move the photos on a regular basis. Services like that tend to organize everything by date, either by default or as the only option. That makes sense, because the date is the only piece of information that software can guarantee it will find.
Personally, I'm not comfortable with using an online service as my only photo storage option. I use an online photo-sharing service as "backup" for a subset of my photos. The rest live on my computer and various hard drives. But keeping at least part of them online makes them retrievable from anywhere.
Bottom line: You don't need to spend a lot of money on software or a lot of time tagging and keywording. If you simply make sure you download photos and videos religously, and at the very least rename them to something useful, you'll significantly increase how findable they are.